It's training that tells you when you can and can't treat a client. It's training that tells you how to avoid any problems arising and how to deal with those problems if they do arise. It's training that informs you of the structure of a healthy nail.
It could be argued that you don't need this information in the case of many clients, but I would say you need this information when dealing with any client to ensure they are safe, healthy and happy with their treatment.
I'm not saying training is pointless, but all what you have listed can be found out on the net if you look hard enough.