Yes you don't ALWAYS need all 4 fingers on wasd, but there are times you certainly do.
Movement in DS3 requires basically 4 fingers in combat as you have to be very mobile. Here's one example of why this is better to play with a controller. Hold down with weapons of the same category It will change your stance to dual wielding. But thanks to DSfix by famed modder Durante, we were finally able to change the rendering resolution and mod. When Dark Souls was initially released on PC, it was clearly a rushed console port.