Regarding the use cases there might be some like stable coins or some kind of contracts like for example a promissory note register to secure non collateralised loans. Or NFTs.
Discussion
Thanks for your two replies.
I understand the trust risk with bridges, indeed. But about the use cases - why couldn't all those run on BTC itself?
You will have to follow Bitcoin network block rules and smart contracts are less flexible in my layman opinion regarding smart contracts.
But I think it is actually better because we keep the main chain cleaner and just for settlements in that way.