The main difference between a zil and a crypto domains is that they exist on different blockchains

The main difference between a .zil and a .crypto domains is that they exist on different blockchains.
A .crypto domain are built on the Ethereum blockchain, the .zil domains are built on the Zilliqa blockchain.
The domain extensions are fundamentally similar and work for both websites and payments.
Right now, Zilliqa has cheaper fees and (on average) faster transaction times, but Ethereum is an older chain with a broader integration of Web3 tools, as well as marketplaces like Opensea and Rarible.
It is important to note that, to the end-user, the underlying blockchain does not significantly change the experience of using the domains. For instance, all domains can be used for accepting payments and issuing decentralized websites.
However, some integrations such as ETHMail and native support for Brave and Opera browsers are not supported for .zil domains.
For the further information: https://medium.com/unstoppabledomains/crypto-ac3eec150768

As of January 2022, Our interface now has support for the top 200 coins/tokens by market cap as compiled by CoinGecko. However, I recommend to check if your wallet supports UD domains as some wallets will require an ETH address to support sending ERC20 tokens to a domain name and might not support the multichain addresses currently available in our interface. You can check available applications here: https://unstoppabledomains.com/apps

For the further information: https://unstoppabledomains.freshdesk.com/support/solutions/articles/48001185621-what-cryptocurrencies-are-currently-supported-

When hosting a website usually you use a dedicated VPS, register a domain, editing your DNS records to point your domain at your server. However if one of them is shut down, you website will shut down. However IPFS and a blockchain domain is decentralized and nobody can shut down. IPFS is peer-to-peer hypermedia protocol

designed to make the web faster, safer, and more open. HTTP looks up resources based on the URL, but IPFS uses hashes to look up resources on its network.

An example of an IPFS hash is QmS4ustL54uo8FzR9455qaxZwuMiUhyvMcX9Ba8nUH4uVv and can be accessed through a gateway like Cloudfare.

This hash points to the starting files for hosting your own IPFS Node and as you can see it only shows links to other files.
But an IPFS hash can also point to a website such as web3.crypto.

Note: You must safeguard your seed phrases and private keys.

Yes, you can.
Here are the steps:
Before you start cloning the zillet.io wallet into MetaMask, please make sure you do a backup of your wallets.
The first step is to take your Seed Phrase from the zillet.io wallet you want to clone. Go to your wallet settings and take the Seed Phrase.
The second step - you need to Log Out from the current MetaMask wallet. This you can do by simply pressing on the big colorful bubble in the top right corner of your MetaMask wallet and the “LOCK” button.
Import your wallet Seed Phrase into MetaMask: You will see the “Import using Secret Recovery Phrase” sign once you Log Out from your current MetaMask wallet.
Once you press this link, you will see the option to enter your Seed Phrase together with the new Password for your MetaMask wallet. This will be your new MetaMask wallet, but the clone from the zillet.io wallet. You can type in 12 or 24-word Seed Phrases - MetaMask supports both ways.
For the further information: https://unstoppabledomains.freshdesk.com/support/solutions/articles/48001186629-cloning-almost-any-ethereum-wallet-to-metamask-desktop

It's completely depends on you, for what purpose, speed, cost, transparency, security and always do your own research. However Ethereum is commonly known as the best blockchain for smart contracts and recommended. Ethereum is a smart contract platform. It is the biggest smart contract platform to date. Ethereum smart contracts are coded in solidity, a language suitable for smart contracts. At its current state, Ethereum is a Proof of Work blockchain network hosting the Ethereum Virtual Machine (EVM), a so-called Turing-complete system. It is famously regarded as being the world’s computer for its ability to simulate a nearly perfect machine.

Ethereum has the "code is law" approach to smart contracts. That means, contracts are locked after they are written. They can't be changed. The only way a smart contract could be changed is a hard fork which is very unlikely to happen.
This provides better decentralization and cryptography secures the tokens. But it has its demerits which is, if a bug is found in the code. It can't be fixed and the developers would have to abandon their tokens and fork it on a new smart contract.
It's used by more people, has a strong community behind it and has many smart contract tutorials about the solidity programming language on YouTube and ethereum.org. It's arguably the strongest blockchain platform for the near future.

Polkadot is yet another smart contract ecosystem which can host parachains on its blockchain network. This means that the platform can run multiple chains inside an existing blockchain, a feature that we know today as sharding. Sharding scales blockchains in the sense that they can process more transactions than usually.

Solana is a project created to solve the blockchain trilemma and bring scalability to smart contracts without damaging decentralization and security.

The platform can supposedly support a record-high of 65,000 transactions per second thanks to its unique Proof of History consensus mechanism.

Binance Smart Chain as an alternative to Ethereum. It is a blockchain that runs in parallel with the original Binance Chain, with the noteworthy difference that BSC supports smart contracts and features compatibility with the EVM.

The blockchain network uses its own Proof of Staked Authority (PoSA) consensus model to process transactions and reward stakers. Blocks are generated every three seconds, and those who actively stake BNB can join as a network validator.