Firefox users don't use profiles, we use something much superior: multi-account containers.
Firefox users don't use profiles because switching between them is a pain in the rear (at least on some platforms). Containers are nice, but you can't have different bookmarks, extensions, settings, etc. It's not a replacement for profiles.
Containers on the other hand, fit the use-case of personas perfectly. I can keep logins separate, keep a work / home session separation, etc. Best of all, I set up certain websites to always use a particular container, even when I'm currently browsing in a different container tab. I can't imagine going back to Chrome profiles.