No, of course you can't read all of the text at 10Mbps. The problem is that when you start some task which has a lot of spew, just having all of that text scrolling past can slow everything down to the point where the task actually takes longer! Even a few percentage points of slowdown can add up to minutes just sitting there twiddling your thumb.
Just a few weeks ago I accidentally ran a command on a remote machine that generated so much spew in the few seconds it ran before I hit control-c that it took 5 minutes to scroll through before I could do anything else.
But yes, you probably want to avoid that much text spew even if your terminal is super fast.
You think that your bottleneck is the terminal emulator, but you are wrong. As the mosh people pointed out a few years ago, the output from the remote machine has to scroll for 5 minutes because it is all backed up in the SSH connection between your machine and the remote one. Your bottleneck isn't in the terminal emulator at all, and changing terminal emulators to whizzy new ones will not make any difference to it.
Just a few weeks ago I accidentally ran a command on a remote machine that generated so much spew in the few seconds it ran before I hit control-c that it took 5 minutes to scroll through before I could do anything else.
But yes, you probably want to avoid that much text spew even if your terminal is super fast.