Think of it this way. You are bonus whoring and you want to play the most raked hands as possible, as fast as possible. That way you clear the bonus and move along.
The other way of thinking of it is you don't get a playable hand each time you get dealt cards, but if you have 4 tables on the go, one of them is bound to have a playable hand. If not, the time til you get a playable hand is much less then if you were playing at one table, thus reducing boredom.