The goal in doing p-tex repair is to prevent a yellow flame. The way to do that is to keep the burning p-tex stick close to the place you are dripping/depositing the melted p-tex. I think the better way is to use a metal scraper, keep the burning p-tex stick close to the scraper until you get to the gouge, then drip the melting p-tex into the gouge from about 1" away. The "closeness" of the demonstration would cause too much dragging of the melted p-tex, which could create air pockets between the melted p-tex and the base itself. Those air pockets will cause the p-tex repair to pull off the base at some point.
The heat of the melting p-tex is the same whether you drip it into place, or use the silly "smearing" technique demonstrated. Neither is more likely to harm the base if the melting p-tex stick is continually moving.
As to the waxing, two faux pas. First is the extremely time-consuming method of "melt wax bar, rub onto base, melt again, rub again, melt again, rub again... etc." It's a whole lot easier to just drip the wax off the iron itself.
Second is the fact that he's using a steam iron without first covering the steam holes. DUH!
Overall, I'm not surprised there are technique errors -- he's repairing a tongue depressor, not a ski.