I emailed david wyllie from victoria wax and here's his reply on why should it be applied by hands.
"Applying wax with the bare hands is not a new technique, it was used in the 60's, and I suspect that it had been used by people at sometime or another over the last 100 years. It just produces the best possible look and protection. Wax is at its very best when the wax from the original jar or tin is in that same concentrations. The hands are non-porous and no carrier
solvents will be absorbed. What is in the jar or tin is now in the proper concentrations on the finish. Bare hand waxing will benefit any wax-based product by any manufacture. In the right hands it could make the difference between a good job and an excellent job. If you are like me, waxing the finish is the final step and the most rewarding. One coat of wax is not enough and ten coats seems reasonable. We are all guilty of over using wax
applicators to the point that we have to wring out the liquid solvent collected every once in a while to continue getting a good mix. And most of us seal the moist wax applicator back in the jar or tin to be ready for the next round of waxing. I am not saying that any one particular technique is for everyone, I just know what I like and find rewarding. If you wish to use a wax applicator, keep a few extra on hand so the wax is applied full
strength and not diluted with the carrier solvent. Too much carrier solvent in an applicator pad could easily remove some of the wax as well. Messaging in and spreading thinly by the bare hands has its benefits too. You could do a test right now, you must have a high-end wax in your collection of car
care products. Just use the finger tips first to apply a small amount to the driver's front top fender. Work it in and message it around, let it stand. Slowly you will see a large amount of wax attaching to the surface. 1000s of small specks of carnauba and other waxes depending on the manufacture's formula. Buff with a clean towel and repeat in a few minutes. A major bonus
to many of the waxes coming to market in the last few year is the use of extremely low (VOC) volatile organic content solvents, many of these solvents are used in the skin care industry and have been adapted with a multitude of different high boiling points and KB ratings. In other words don't bare hand a wax that is stinky."