Isn't core strength and good stance part of the toolbox for winning a fight? If those same exercises were to incorporate punching movements and kicking movements and blocking movements, to add some exercise and help train the muscle memory, those would be forms. Would they lose any functionality? No. Would they gain any? Some, though I don't know how much, since I've never trained heavily in a style that used forms of that type.Yeah, but you guys don't believe that there's some secret techniques in those movements that teaches you how to fight. You guys recognize that you're only doing those excercises to develop your core.
I mean Yoga has some pretty weird poses that develop flexibility and stamina, but I would never call Yoga a kata or martial art form.
The idea of "secret techniques" is, IMO, more marketing than realistic. The times I've had someone explain the secondary level of a kata (I suppose that's the bunkai?), it was just another way to see the movements - another set of responses that used some of the same actions. There was nothing secret, just something they didn't teach to new students, so as not to overwhelm them.
I've actually been working on a set of forms like this for my students, to be able to help them learn new techniques by saying, "Okay, you're going to be using this footwork combination from the first kata." Basically, they should help the less-coordinated and less-experienced students improve their movement on their own. It'd also be a tool for highly motivated students who wish I offered more classes, so they can practice more on their own.