Day in, day out, having the entire body seated at their desks for hours at a time.
What amazing things will suddenly start getting accomplished because of this?
Especially after the first few years of getting grounded in parliamentary procedure, there's little purpose to spending enormous time in chamber.
Now, some take this too far. Others fill that time with dialing for dollars. Yet others, however, focus less on D.C. and run a potent constituent services office back in their home district/state.