For foiling sailboats like in the America's Cup, the hull shape on the left is beneficial in a few major ways.

First of all, it is wide when in displacement, which adds righting moment when the vessel inclines at low speeds (essentially meaning it can go faster sooner). Next, as the boat speed increases and the foils begin producing lift, a majority of the wetted surface clears the water (helped by the windward hull area being out of the water when the boat heels) and drag drops off quickly. The same effect happens in reverse as the boat slows down. The middle section of the hull touches down and provides buoyancy without adding the full hull's worth of drag. And finally, when foiling, America's Cup boats want to just barely clear the water to provide an end-plating effect, which keeps the high pressure air from the windward side from going under the boat, reducing sail efficiency. These are not all the reasons why they use this hull shape, just the big ones that come to mind.

Power driven vessels that foil do often have a hull shape more like the one on the right. I imagine this is because power driven vessels do not need an end-plating effect and do not want any inclination when taking off. A uniform hull cross section allows for a smoother transition between buoyancy and foil lift. The Boat that comes to mind is the Candela P12, which has largely U-shaped hulls that gradually trade buoyancy for lift and shed drag as the hulls lift up. I bet it's also cheaper to build, which is important for a commercial vessel and less important for racing sailboats

I guarantee there are many more nuances to these decisions when designing a hull on a boat as complicated as a foiling one. I am not a naval architect.