Useful to me!
I have been looking at a lot of homemade ones, on youtube. Mainly to see how closely they resemble the official (IDPA etc) safety rules, to see if I can pick up additional useful tips. Most are pitiful.
This one seemed useful to me.
YouTube - Gun Safety by Nutnfancy
Also I note nssf (the OP vid) is available online
NSSF
I wonder if it has been updated.