With pipx when you install things they go into isolated environments. With pip you're just installing things globally.
This difference is important due to dependencies- if you have two different CLI tools you want to install but they have conflicting dependencies then pip is going to put at least one of them into an unusable state, while pipx will allow them to both coexist on the same system.
I haven't used pipx, but as far as I understand, pipx = pip + venv.
If your pip executable is in a virtualenv, the "globally installed" is locally installed.
pipx, poetry, pipenv and co are still nice wrappers to have, I suppose. It just feel less useful now that most of my projects are dockerized.
This difference is important due to dependencies- if you have two different CLI tools you want to install but they have conflicting dependencies then pip is going to put at least one of them into an unusable state, while pipx will allow them to both coexist on the same system.