I log into Chrome with my Gmail account and my browsing history+passwords are carried across all the devices I use in a typical week, Windows, Mac, iPhone. This is huge, as I rely on history a lot.
My last 3 jobs also had Google-based accounts, which means I'm able to maintain two browser contexts where I don't dirty up my personal history with boring work stuff.
I assume Firefox probably offers account syncing, but there's no reason to switch at this point. They lost me more than a decade ago, I loved Chrome's out-of-the-box interface. It made Firefox seem ancient and cluttered with all the unnecessary buttons, and massive borders and tabs consuming precious screen space.
edit: And I'm now reading that Firefox supports multiple browser contexts but requires some effort. No thanks.