It depends vag, there is never really a "need" to learn a power clean from the floor if jumping is what you are targeting. The first pull is just getting the bar into place for the more explosive second pull, which along with the catch, is what you are after in the exercise to begin with. It really depends on the athlete and which one they are better at. Its easier for a lot of guys to learn to "jump" the bar up using the hang position, in a short period of time. Starting from the floor, youre going to see lots of jerking the bar up without getting to the positions and joint angles you want, to put them in the actual jumping position.
You also have the option of dipping down to load the legs from the hang, that you dont get with the floor versions. There is still a double knee bend if done correctly from the floor, but its not in the same vertical/downward vector, and is still a different movement pattern. Both are good exercises, but a power clean from the floor is more specific to olympic lifting than it is to jumping, starting from the floor is a rule for them.
As long as you are jumping (explosive strength) and catching (reactive strength), a WEIGHT, a set and constant distance, any differences will be minimal. Both are good exercises, just have to factor in what youre trying to accomplish and what the athlete is doing the exercise for in the first place.