This is only my personal experience of course, but for making little tools for automating tasks or prototyping ideas quickly AI has been a game-changer. For web development the difference is also huge.
The biggest improvement is when I'm trying something completely new to me. It's possible to confidently go in blind and get something done quickly.
When it comes to serious engineering of novel algorithms it's completely useless, but most devs don't spend their days doing that.
I've also found that getting a software job is much harder lately. The bar is extremely high. This could be explained by AI, but it could also be that the supply of devs has increased.
AI has has been the opposite for me. By doing all the easy stuff for me, it's allowed me to spend most of my time solving hard problems and being creative, instead of spending most of my time doing gruntwork. If anything I'm more sharp than I used to. It's a double-edged sword.