
Contributing expert Olaf Vancura, Ph.D., writes:
In general, and ignoring card counting, there is no difference in expected outcome for one hand of $10 vs. two hands of $5 each; however, there's a slight risk consideration. In principle, playing two hands has a slightly lower volatility, which means the risk of winning or losing the full $10 is less. From an entertainment standpoint, playing two hands is also more fun. But there's an additional practical consideration. Most casinos impose a greater minimum for playing multiple hands -- usually at least two times the table minimum. So if you're at a $5 table, you'd have to bet $10 per hand, or $20 total. This consideration might be enough to keep you playing at one hand of $10.
As to the effect on card counters, mixing one and two hands can be used to disguise bet variation. A card counter may also wish to use multiple hands to control how many cards are depleted per round.