I don't agree with you here -- every kit, piece of gear, training class, and so on should be judged by the requirements of the person considering it.

For example, it might make sense for someone on this thread (not necessarily you, Jeanette_Isabelle) to take a "basics of cybersecurity" class to educate that person on avoiding account takeovers, scams, malware infections and so on. But for me to take such a class is less valuable, as I usually teach them.

Similarly, our medical professionals probably would not get a lot of benefit out of an 8-hour refresher on treating gunshot wounds for firearms instructors. I try to take such a class every year, and I've learned something from each one.

A kit that I built makes sense for me -- it's designed around my skillset and the problems I think I might face. I think most of us here, if we're buying a pre-built kit, it's with an eye to supplement or improve upon it for our purposes.