I like this about perforce too. Another thing I like is that I can easily substitute subdirectories with other ones, or mask out directories I don't need. I can swap in the new code for a single module into a legacy version with a one line config change.

I also get the ability to use the depo explorer to poke around at absolutely everything that folks are working on. The search function in gitlab is basically a joke compared to this.

Unfortunately for perforce, git/gitlab seems better in basically every other way. It took me 2 years to have anything nice to say about perforce, my regular development flows we're just that painful.