If I play a 10:1 spread (Wonging <-2) on the games offered near me with a $25 unit and a $15k bankroll, I can make $86/hr with a standard deviation (SD) of $1050/hr and a 9.5% risk of ruin (RoR) per CVCX. However, if I play the same way except that I play two hands at +2 and above (adjusting so that the total wagered per round is the same as if I were to just play one hand), my hourly EV goes down to $73, but with an hourly SD of $825 and a RoR of 3.9%. If I were to play a little more aggressively at +3 and +4, I could get almost the same hourly rate with a 5% RoR.
Therefore, we can conclude that all else equal, you can make more per hour playing just one hand, but with a much higher risk and higher variance. Opening up to two hands as the advantage goes to the player helps to smooth out the variance and reduce risk with a small sacrifice to EV.