someone I "know" through friend-of-a-friend got one of these done. He is a professional craftsperson.
He talked about it on a video here (maybe around 3:30)
https://www.benuyeda.com/tattoo
It seems like an interesting idea but as far as I'm concerned you're still eyeballing-- no different from the 1-cm-ish pinky width or the 1-inch-ish terminal digit of the thumb, 10-cm 4-fingers-together, etc. for eyeballing stuff it works fine, but I don't think anyone's doing finish carpentry with tattooed measurements....
regardless of whether the size changes, the lines are going to move every time you move your body (the tension on your skin changes the aspect of the tattoo).
Still, it did come out very cool looking.