It was way too easy for the venv to be the only artifact of the process used to produce it. pip install, hit a bug, install some other dep, another bug, oh this one needs to be downgraded, and so on until it works. Without more effort to memorialize / remember the steps, deleting the venv destroyed the work to create it.

uv, in addition to its raw speed, is very clever to record things in pyproject as the user interacts with it.

Sure, but you can have pet venvs with uv too.

These are tools, if you choose to hold them wrong no one can stop you. uv didn't invent the screw driver or the knife, its novelty is as a Swiss Army Knife which put them all in one.