No. But the hand plane does produce a better surface when taking a shallower cut. That's the thing with adjustable feed speed. Usually, the cutter head speed is constant. So, at 1/2 feed speed, you're taking half sized bites across the horizontal plane with every pass. A thickness planer doesn't work exactly like a hand plane. It takes out little scoops instead of long shavings. But both tools tend to make smoother cuts when taking smaller bites, because the wood you're removing is more weakly connected to the wood in front of the blade. So, it's less likely to pull it up with the section of wood your blade is engaged with, and tear it out.
Slower feed speeds are especially handy on boards with reversing or figured grain, where no matter which direction you feed the board, some of it is going to be against the grain. That, combined with a shallower cut, can really help a lot on potentially problematic wood.
But yeah, feeding in the proper direction is definitely far more important than feed speed. I'd even argue that depth of cut is more important as well. A slower feed speed is just another arrow in the quiver to deploy, should you need it.