I don't think so as smart contracts have huge issues unsolved.

It also doesn't solve a problem we haven already solved; If i buy something, companies are quite aware how this default contract works and what are up and downside of doing business with someone.

In smart contracts you remove the trust these people build and now come up with another mechanism. The latest i'm aware of is blocking capital from both sides until transaction is done. This binds a lot more capital on both sides which might be a huge problem for a small company vs. a big one, it could alos kill one party if the other party never accepts any resolution.

A current LLM with a credit card an already just buy something and everything in the background works as it has for a long time.

Fun for the first person that prompt injects their way to a billion dollars, I suppose?