Opensea can only make your NFTs useless on Opensea, that's the difference. You can still trade them on Looksrare or other marketplaces. Metamask is the same, i

Opensea can only make your NFTs useless on Opensea, that's the difference. You can still trade them on Looksrare or other marketplaces. Metamask is the same, if you can't use it you can easily take your coins to another wallet and use them there, you just import your seed phrase.