If you don't log in into websites, I don't see why you would leave yourself exposed and very easily hacked with Firefox or private browsing if there's Tor.
Private browsing is NOT secure. It's just a shortcut to avoid clearing your history manually. ANYONE can see who you are, and what sites you visit with easy-to-use tools that are available online for free.
Security is not an absolute. The best you can do is talk about whether something addresses a particular threat model.
There are different tradeoffs to Tor. A big downside is that unencrypted traffic is now easier for intermediaries to read and even change, because of how exit nodes work.
Yes, I was just thinking the same thing. I can almost imagine a world where software believes me about what kind of experience I want, "full site" on mobile or "mobile site" on the desktop, rather than browser sniffing followed by awkward clicking around to correct its misapprehensions.
The features you explained are exactly what I was looking for in a mobile browser. In fact, i wish they launch Focus for Desktops operating systems too.