When (or why even) use PLPython(3)u

As I gain more experience with PostgreSQL I start to question the existence of PLPython. It's considered an "untrusted" language https://www.postgresql.org/docs/10/plpython.html What I am wondering is, when or why would anyone need to use this? PLPGSQL is already quite a strong language that allows you to do a lot of things. Has anyone here had the need to use it, and if so, for what?