> Why would you even use python without uv anymore

Probably wouldn't:

https://mise.jdx.dev/mise-cookbook/python.html#mise-uv

> have a system python binary and virtual envs linked to it

I'm not sure if you're saying avoid using system python?

In my experience so far, you never want to develop complex software locked to system versions of runtimes. Too often you need a bleeding edge feature, or conversely need to postpone updating due to needing an old version for some reason.