Why Dual Gas Tanks

Hey, after years of fishing out of a runabout, I'm about to make the
plunge. I've narrowed down my boat choices, but there is one
difference between the boats that I don't understand.

Complicating matters, the sales guys don't have a good answer either.

One has a large single gas tank, the other has smaller dual tanks.

Are boats with smaller tanks more stable in rough water because the
fuel does not whip into a side to side, slosh frenzy?

Any advice would be appreciated.

S.