My experience has been that cruft accumulates and creates back pressure via growing token usage.

The APIs aren’t clean, which creates indirections to other parts of the codebase to check on leaking abstractions. It doesn’t learn, though, so you pay for those indirections every time (right now, anyways).

I’ve not been impressed with its ability to clean that up with a generic “make it gud” kind of prompt. I have to point it at something crufty, but it will fix it then

I agree, but for some projects, that first vibed version is just about good enough and becomes the final version. I have a few things like that and it was nice not to have to bother.

For work stuff, I don't dare 'vibing' anything, and force myself through torturous design cycles and regular refactoring runs. But thats serious stuff with hundreds of thousands of users.