Been using profiles for some years now and they are great. I usually start with the default profile, then navigate to "about:profiles" to open all I need. Thanks to profiles, when my manjaro install broke, I migrated to NixOS and all my browsing sessions were ready to use the way I left them. Getting a dedicated, more integrated UI for managing profile will be great.

The one thing I'm missing is "incognito" profiles - e.g. spawn a temporary profile (without any identity attached) easily when I'm researching/navigating unusual sites and kill it once I'm done. Having multiple of these would be a great improvement over normal incognito windows (which share identities).