Is it really that bad/fast? I had to watch to video to see what you meant, but in reality I just saw a tempo and way of shaving that mimicks my own speed. It's all in the hand/muscle memory. After a while using the same razor it's just an extension of your hand and you'll wield it like you were born with it
I actually have to slow down when I a seldom time a year use a cartridge. Because I almost never use one. So for speed and convenience, I have absolutely no use for a cartridge. I only mention this because I came to think of the common advice to use a cartridge if one's in a hurry.