just from first principles its really not. given its propensity to just make shit up and cheat, ai is really useful when there is some kind of formal or exhaustive checking as a wall for it to throw crap at. so if you rigorously define success and spend a bunch of tokens, you could easily save time and money. but if you ask the ai 'is this correct' and it says 'yes!', or even 'no!', then you've really learned nothing. this isn't a can you can kick arbitrarily far down the road.

I think writing tests is a great use of ai, but only if the tests themselves are throughly reviewed or are themselves validated by statements in a formal system.