My experience is that sometimes they give you a 10x speedup but then you hit a wall and take 30 times longer to do a simple thing and a lot of people just keep hammering because of the first feeling. Outside of boilerplate, I haven't seen it be this magical tool people keep claiming it is.
That's the definition of an advanced scaffolding tool. And yes, I subscribe to that. From time to time I use Gemini CLI for little tools I have no time to read all the docs of thinkgs I'm not used to, but in the end I need to make flow changes and be forced to understand the generated code. x10 faster bootstrap, x30 slower manual changes, 100% my codebase problem.