It requires limited bandwidth; at a rate of perhaps a few words per second.
It therefore required considerable bandwidth for a large number of users.
Also, displaying video over the internet requires more bandwidth.
Video required more bandwidth than might be available during combat.
The return-path was originally only used for some control signals to order movies, etc., which required very little bandwidth.
This is impossible to achieve in physical systems, as it would require infinite bandwidth.
I assume thats why you'd be paying more for 1st party services, it requires more bandwidth.
That's not really a choice when the applications I use require decent bandwidth.
So really most of the data is uploading the raw voice data (which doesn't require much bandwidth).
They all require bandwidth to deliver their products and services.