Matagusanos:After all, it works the same way as many equipment features. You may always pay for a tube of premium balls or some iron set and get a slowed down meter (and / or extra distance, back spin, accuracy...).
True, however you are not allowed in the middle of a round or hole to decide you would rather play a different ball for this particular shot, pick up your ball and put a different ball down in its place, and then after you hit your 1 shot then start using your original ball again.
Or another way to look at: you are not allowed to go get a 15th club just for that one particular shot. You are only allowed 14 clubs in your bag, your choice on the 1st tee, not switch in out of different clubs once you start playing a round.
Might be a worthwhile feature for practicing/mulligans with different balls/clubs, however not allowed for a tournament round which is just cheating or a 2 stroke penalty for every occurrence.