You are talking about the actual Firefox Profiles and not about Container Tabs, right? https://support.mozilla.org/en-US/kb/profile-manager-create-...
You can also get to an alternative, somewhat more Chrome-like profile manager by typing "about:profiles" into the URL-bar.
I'm a FF user since the days of Phoenix but the profile management is something I've relied upon Chrome for in recent years.
That "create as many arbitrary profiles as you like!" feature is awesome for testing some kinds of web applications. Last year, I worked on an in-browser chat project. At some points I really needed to have 4-5 different users logged in simultaneously so I could send messages back and forth and track down some bugs.
Another common scenario: suppose you're developing, testing, or supporting a web application where the user experience differs depending on a user's permissions. Can be a lifesaver to have multiple browser windows, each using a different browser profile + app login, simultaneously. Rather than repeatedly logging in/out with a single browser window.
FF's Container Tabs are an interesting feature. They could get some adoption. Similar underlying technology I guess, but different (more restrictive) UI meant to guide users down a specific path. That's cool; hopefully it can be extended at some point to allow a set of arbitrary accounts to be created by devs, testers, support folks, and others.
But the ability to keep work and home separate - separate bookmarks, extensions, etc. is really valuable. And although it's possible with Firefox, it can still be a little quirky having to setup custom Windows shortcuts, etc.
I'll check out about:profiles. Not sure I've ever seen it.