Separate browsers too, for me it's just super unpractical to always have to open a new browser window just to open facebook, personal email, work slack etc.

Tree tabs then makes its super convenient to navigate between these worlds.

I know I'm nowhere near the mainstream, but lack of tree tabs is the showstopper for me with Chrome.

You may not have been suggesting otherwise, but in case you're not aware, Firefox also has user profiles and can have multiple open at once.

not so much by default. first you have to launch firefox with a special flag. if firefox is your default browser, and your session started by clicking a link in a different program, youd have to close your browser and click the right shortcut.

unless I am mistaken and -no-remote isnt required anymore.

I love how profiles make separate extensions a feature. I can keep useful-but-rarely used extensions in a separate browser profile instead of installing/uninstalling/deciding re: extensions.