Profiles provide separate bookmarks and add-ons per profile. I don't think containers do. Containers seem to be more about making it so you can appear as different people to different sites. Profiles are more about letting you separate roles.
For different things I do during development, I want different sets of cookies, bookmarks, history, and add-ons. With profiles, I get that, effectively getting a separate browser that I can extensively customize to its particular task.
Those were actually what I was thinking of when I said Chrome handles profiles better. Firefox has the functionality, but it doesn't have as nice an interface to it. Chrome, for example, on MacOS puts the available profiles on the right-click menu on its dock icon.
Do Containers support segregated browsing history yet? That's what I've liked most about Chrome profiles. I can have a "personal" profile and then a "work" profile that doesn't comingle the browsing history. It's convenient when on a screenshare--the URL bar's type-ahead won't reveal your personal browsing history.
You can have multiple profiles in Firefox too. If you start Firefox with the "-P" flag, it brings up the profile manager, which allows you create/delete profiles or start Firefox with a selected profile.
You can also start/manage profiles from inside Firefox by navigating to about:profiles.
I think that Containers available on Firefox are much better than profiles