Wait, not so fast...True, S100/P21S is probably the easiest paste wax Ive ever seen to apply and remove by hand.
But, Ive also been using mY PC and a finishing pad to apply paste waxes, to excellent effect...I personally prefer to apply pastes by PC because I find I can get a very uniform distribution, rubbed well into the surface. To go quicker, I have an 8" Meguiars finishing pad I use on the 6" PC backing pad...I would never use an 8" pad for polishing because when I polish, Im usually attacking a specific area where there is some scratching...But for an overall application of wax, the 8" pad works very well, and is quicker.
So, the PC applies it uniformly, rubs it in good, and goes quickly. I speed of from 2 to 4 works best....I just use a putty knife, dragged across the paste surface to grab some, and butter the pad with it. I can control the quantity easily this way, and will use no more than if I were loading a hand foam applicator. Some guys use a hand foam applicator, dragged across the paste surface, to gather the paste, and use this to apply it to the machine foam applicator.
So, in summary, I think both hand, and PC can be effectively used to apply and remove the paste...I dont think one has any inherant advantages over the other..its strictly a personal choice.