I totally agree with you. In my opinion, ground fault fonction and overcurrent fonction work well, since a long time. The both = GFCI. It detects contacts between phase and ground and possibly between neutral and ground and phase-neutral.(in wiring, J-box or appliances). What more with an AFCI ? I dont know. And in this video, no arc. I imagine that rule was intentionally violated to generate a glowing connection, because GC apper often after month or years. I think video highlights that "glowing connections" are undetectable, even if the rules are NOT VIOLATED.
Regards,
