Mainly the "project" system. I'm only developing python in my free time, not professionally so I'm not as well versed in its ecosystem as I would be in PHP. The fact that there's tons of way to have project-like stuff I don't want to deal with thoses. I used to do raw python containers + requirements.txt but the DX was absolutely not enjoyable. I'm just used to it now
To be clear though, we only use uv in the builder stage of our docker builds, there is no uv in the final image.