And I've seen those too, children who have generally good form, but have no reasonable expectation of defending themselves against a schoolyard bully, much less an adult intent on harming them. Do you know what I am talking about? A kick that looks nice in the air but cannot even push away a fifty lbs. heavy bag... A child that knows the choreography of the form but has no focus, no intensity. To them, the form IS a dance rather than a fight.
In my style, a black belt means you are combat effective. You might not be the toughest guy on the block, but you should have a reasonable expectation that your hard-won skills will translate into something useful on street.
I know what you mean, and I agree. Again, this goes back to what I said before about being able to make the stuff work. I have no issue with a JR BB, but if they did away with them, I wouldn't lose sleep over it either. This is why I think that its crazy to see a 4yo in a class. Its more babysitting for the parents, than anything else. Have a min. age to start and a min. age for BB. If thats done, then theres no need to the Jr. BB.
Getting back to your first paragraph. Again, I agree. People can look real cool doing kata in the air, but ask them for some application, ask them to do a move from the kata on someone....forget it. Same for SD. Looks flashy and cool in the air, but put a body in front of them, and things are much different.