Again, performance and battery life is going to be better with Apple’s approach for mobile devices, especially since iOS devices have hardware accelerated playback.
Web browser considerations aren't relevant on iOS because Apple forbids alternative browser engines. Firefox on iOS is not Firefox because Apple doesn't allow it to use Firefox's JS runtime or Firefox's render engine. As a result there isn't any true browser competition on the iOS platform, which is a shame.
Personally, I want to run full, real Firefox on my iPhone. It's a low quality move from Apple that they stop me doing that.
