Disagree on the technical aspects. It'd be inexpensive to monitor adversary military activities on the lunar far side: one lunar satellite would do it. The gravity well is not trivial, and any launches from the surface (should this become a thing) would be immediately visible from high orbit, by the intense infrared glow of rocket combustion exhaust. (Exact same way nuclear early warning systems work on Earth, for that matter[0]).

Agree that the general concept is a serious one, but I don't think the numbers work out on your specific implementation.

[0] https://en.wikipedia.org/wiki/Defense_Support_Program#Histor...