I never understood the appeal of that procedure. You still have to shave down to a 0, just like you would if you just went sly. You would be stuck doing it, in fact because it would look weird if the horseshoe grew out even a little. Just seems like a lot of money and effort to seem like you are a NW1 who is shaving their head voluntarily. And what would it look like later on? I mean tattoos fade over time. The only way I would ever consider it is to try to add illusion of density to a hair transplant.
I'm no expert on it but I believe the optimal idea is for people with a decent hairline and very poor density to keep their hair at 0 guard and use the dots to make it look like hair. It rarely looks plausible but I have seen a few decent looking ones. Most of the images you'll see advertised are ridiculous completely sly bald, and super packed right across with a laser ruler straight line, and they look like a cartoon.
And they fade as well, actually needs to be touched up every 18 months to 2 years.