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.
