Mapped projections have been a thing for a while now, but why aren't people mounting projectors and dancing carefully choreographed moves to match a projection on their bodies?
I must admit, I wasn't taking a shower when I had that thought.
In 2018 a tv commercial premiered this projector mapping tech during a Superbowl commercial for Ponds cold cream...
https://www.youtube.com/watch?v=XvDtMeKgcio
The behind the scenes video...
https://www.youtube.com/watch?v=dCQGarGxRXM
This video illustrates that the answer to OP's question is: because in almost all cases it's probably cheaper and more flexible to do it in CGI. The only time projector mapping would be useful would be on live performances.
Which would be cool, but probably too subtle or constrained for the audience to appreciate? Like, how far can the projectors be, and how bright to overcome stage lighting? How much can the actors move? In the Pond ad, the model moves, but very subtly. I noticed it most when she makes a slight shaking movement to coincide with the makeup "falling off." There are no sharp movements.
Projection mapping software generally assumes the surface(s) you are projecting onto is stationary. You might need special software to target a moving object
I do feel like this would be very difficult with the inconsistencies of human movement. Would be difficult to get the projections to line up. That said, people have done similar stuff, mostly early Pomplamoose music videos
https://youtu.be/i7X8ZnmLfM0, https://youtu.be/dm3ZEMQf98k, https://youtu.be/tk4_SMI0jVc
I would also consider Ok Go's "I'm Not Through" commercial to be similar in concept.
Check out touch designer. I was doing this for fun about 10 years ago and I know more professional creatives use it for the same thing. These days I think the camera tracking is pretty good but you can use a kinect for better tracking. Bit of a learning curve but if you have an aptitude for visual arts and programing you will be fine.
Were you dancing at the time?
I imagine it's not as easy in terms of producing the template video to match your body type (and maybe agility) and then to set up the projection just at the right distance. Conventional wisdom might also say that you learn dance moves better by copying others and that's why you get floor to ceiling mirrors in dance studios.