Perforce is used in game dev since it handles binary files super well, and is used by many people who aren't engineers. It's not perfect, but it's super easy to use and the GUI tooling is amazing.
I've used Perforce before moving to Git (and used rc and svn before that), everyone has had the same issues with one team member knowing it better and being to go to person for resolving issue. With Perforce the GUI is okay, or at least it was 10 years ago when I was using it, but we always went to the cli interface for many things not supported in the GUI. A GUI can't cover every option and be usable. Visual metaphors are more accessible initially but eventually they become overwhelmed and you need to move to linguistic metaphors like the cli and code.
I cringe everytime I'm forced to use perforce for work. Every action is more convoluted, slow and painful compared to git. Perforce might be great for binary files and non-technical users. But there is absolutely no reason to choose it over git when working with source code.