I would say such inventions are as old as 30 years when i first heard of startups / inventors trying to do such stuff. Obviously the tech must be now much more mature. Still, it never got off back then because typing was magnitudes faster than what ever you could do with your hands alone. Learning to do such hand motions had a similiar fate as why alt keyboard layouts always stayed niche - most people have no patience to learn that complicated stuff when they already have learned something early on that works.

Heck, I’m just excited to potentially have more meta keys.