Two different jobs. That’s why a lot of tutorials do both.
Brushing it on the nail plate is the actual cuticle-remover work. It dissolves that dead film so your polish has something to grip and doesn’t start lifting at the base a day later. Swiping it around the eponychium is a softening move, so the fold pushes back easily and looks tidy on camera. Nothing wrong with it, but the goal there is pushing. In a thirty-second clip the two look identical.
Dead tissue on the plate takes a few weeks to build up, so if you’re using it every time you paint your nails you’re mostly putting potassium hydroxide on skin that has nothing left to give. Every two or three weeks here (but other opinions differ). In between, I push back after a shower and leave it. Dry-skin months, maybe a bit more often, but doing it as needed is better than doing it because you have a routine for it.