First, I am not sure I see why people seem to be objecting to people that age getting that kind of training. If people can explain that, I would appreciate it.
Next, I hope everyone understands the benefit of making such training a part of an approved program. It is the reason why you as an instructor want that cool class you created recognized as a distinctive specialty--liability protection. If you create a program on your own and teach it on your own, if there is an accident on a dive, the burden will be on you to prove that the course requirements were safe and within accepted limits of scuba instruction. If you create a program on your own and get it approved by a dive agency, if there is an accident on a dive, you can point to that approval as evidence that the course was within accepted limits of scuba instruction, and the plaintiff will have a very hard time proving you are wrong.