I think maybe this is similar to the situation for smoke alarms and smoke detectors. The NEC doesn’t specifically require them, but our state building code does and also specifies their location as well as the type of sensors used.
Seems to be basically the same thing now with CSST. IMO, other than what’s addressed in 250.104[B], it’s not really an NEC issue, so much as a building code and plumbing code issue. Here we just run a #6 CU bonding conductor to the gas piping manifold or location where the gas piping changes over from black iron to CSST. Our state actually banned using CSST for a short time until manufactures addressed the problem of lightning strike damage, so this seems to be the solution the manufactures came up with, and what the state building and plumbing code Dept’s accepted.
