You're other points are much more interesting though. One of my biggest gripes with the other leading browsers is they often feel "foreign" on your host OS (which isn't Windows in my case, but that is just personal preference).
You keep the engine and the architecture around it but add your own luxuries and niceties.
Edge on iOS and Android will have a built-in adblocker soon.
In fairness, bar the "integrates well" point, any modern browser will do what you've described (where "efficient" can be used to described a number of different performance related matrix).
Well - for some of us it matters that the rendering engine behaviour and performance characteristics are the same.
You mean the same AdBlock Plus that allows selected ads to bypass it so long as you paid them?