Yeah I think that martial artists of yesteryear hid their art. Teachers hid it from others so that they would have an advantage, one up, on a potential attacker.
The American Military has on occasion blown up it’s own downed aircraft. They make sure the pilot(s) are clear of the wreckage, they lock in on the aircraft, swoop in and, boom! disintegrated. This ensures that the technology doesn’t fall into the enemies hands. The technology is the edge that makes the difference. That technology means the we win, you lose.
However, the American Military didn’t hide how to use the aircraft from the pilot. I am confident that this conversation between the engineers and the instructors never took place. “Hey Chet, let’s make this Stealth Fighter hard to fly and then hide some of the skills needed to fly it from the pilot! No, no, no, wait, wait, aaaaannd we’ll teach some of the skills backward, yeah! That’s it, brilliant, done and done.”
It makes no sense at all. So if we take this real-world example to the world of kata it makes no sense to hide, obfuscate, or try to bury a technique to be found out after years of hard study.
I would go on to point out that way back in yester-lore, people didn’t have as much free time, so the time allotted to martial arts was the purview of the military, the rich, and those few dedicated people that fall into the remaining categories of society.
So not much free time means I want to be able to apply my self-defense skills as fast as possible and do it well, hiding my skill from the bad guy until I need to show it, yeah that makes sense. Taking time away from making food and shelter and spending on some mind game…not so much.
So hiding from the bad guys, yes absolutely. Hiding from the end user, no, not at all.