I like uv run and uvx like the swiss army knifes of python that they are, but PEP 723 stuff I think is mostly just a gimmick. I'm not convinced it's more than a cool trick.
It's useful for people who don't want to create a "project" or otherwise think about the "ecosystem". People who, if they share their code at all, will email it to coworkers or something. It lets you get by without a pyproject.toml file etc.