I believe this has been discussed in previous years. The discussion was based around maintaining safety compliance in foreign countries. In the USA, the mods themselves could utilize just a rocker switch because the mods can only be activated via the 18R2/3 which has both a physical key switch and manually activated ARM/DISARM function. Placing a similar keyed setup on the mods themselves ensured compliance was not going to be an issue internationally.

Pretty sure they key switch is there to help with NFPA and other safety standards. I would agree that most people never remove the keys from the modules but it is still an option for those who do truly want the modules to not be turned on unexpectedly or by people no authorized.

Probably too much liability in them selling products with saftey features taken off. Most pro shoots require keys for equipment.