Will there be an option for 4k?
It is targeting mostly people which have a slow connection but some may also have a good connection too.
I think so but probably not for all the content. YourDef is a good idea. You don't need 4k streams on a phone.
Of course not. But it would be nice to have that option in case you have a good internet and 4k tv. 4k on mobile would be wasted of course.