> And in particular it doesn't give me much benefit over conda/mamba.
How about the advantage of not taking an entire lunch break to resolve the environment every time you go to install a new library?
That was the biggest sticking point with conda/mamba for me. It's been a few years since I last used them but in particular with geospatial packages I would often run into issues.
This is not the case anymore. With libmamba I've never waited more than a few minutes for resolving dependencies and installing. uv is faster for sure, but speed is no longer a big problem with conda
libmamba solved this year's ago. The dep solver is now much faster.