I do read it. In my experience the project will quickly turn into crap if you don't. You do need to steer it at a level of granularity that's appropriate for the problem.
Also, as I said, I've been coding for a long time. The ability to read the code relatively quickly is important, and this won't work for early novices.
The time saving comes almost entirely from having to type less, having to Google around for documentation or examples less, and not having to do long debugging sessions to find brainfart-type errors.
I could imagine that there's a subset of ultra experienced coders who have basically memorized nearly all relevant docs and who don't brainfart anymore... For them this would indeed be useless.
I mean, I'm curious what kind of code it's saving you time on. For me, it's worse than useless, because no prompt I could write would really account for the downwind effects in systems that have (1) multiple databases with custom schema, (2) a back-end layer doing user validations while dispatching data, (3) front-end visual effects / art / animation that the LLM can't see or interpret, all working in harmony. Those may be in 4 different languages, but the LLM really just can't get a handle on what's going on well enough. Just ends up hitting its head on a wall or writing mostly garbage.
I have not memorized all the docs to JS, TS, PHP, Python, SCSS, C++, and flavors of SQL. I have an intuition about what question I need to ask, if I can't figure something out on my own, and occasionally an LLM will surface the answer to that faster than I can find it elsewhere... but they are nowhere near being able to write code that you could confidently deploy in a professional environment.