I can let my kids play on my computer without them screwing up my personal browser history or getting into any of my accounts without having to teach them how to use yet another extension.

Vivaldi has a great example of profile management where I can literally create a desktop shortcut for each person that uses my computer, complete with their name, and it's their own separate internet profile.

Yes, I'm aware I could solve this problem by using multiple user profiles on my computer, but the overhead and the amount of management would also be a massive headache. It is just far easier to do this.