Sometime, I can ban people from using my tools. It's very very rare and you really have to push hard to get banned. There are less than 10 people on my banned list: it's a VIP club, and 99.9999% of the tezos community members will never be admitted in that club, whatever the 0.0001% on that list will try to make you believe by whining on twitter about how unfair life is, how nobody like them, and how much they are a victim of the system.
The Gas station allow you to see mempool transactions (aka transactions waiting to be processed by nodes) and see how much gas fee each buyer set.
It's a DEDICATED wallet for the live feed and the gas station tool. It must be a wallet different from your main wallet, and only filled with the tezos needed for your next few buys and/or transactions. It's only mandatory if you want to activate autobuy features in the live feed or the gas station tool. If you don't want to use these features, you don't need a prepaid wallet.
To use a prepaid wallet, you need to enter your private key, which is specific to that wallet address: IT'S NOT YOUR SEED WORDS. The tools will refuse any seed words. In Temple Wallet, you can reveal the private key associated with a wallet from the settings of that wallet. For other wallets, Google is your friend.
YOUR PRIVATE KEY NEVER LEAVE YOUR BROWSER. Don't take my words for granted, audit network requests in your javascript console to confirm this. Your private key is also stored encrypted, to limit risk of exposure (malicious extensions or injection of external code). But if your key is ever compromised by someone getting access to your browser and being able to decrypt your wallet private key, the fact that you use a prepaid wallet will mitigate your loss: at most you lose what is inside this specific wallet (hence the use of a private key instead of seed words, which would give a hacker access to every wallet for every blockchain where you would use the same seed words).
It's up to you to decide if this risk is worth it for the convenience of using autobuy features that allow you to be almost sure to get a mint from a specific artist or project, even when you are not able to be on your computer at the minting time.