Isn't this the same as what's being discussed for the coin catalog. https://en.numista.com/forum/topic125051.html
IMO the type (NCLT, etc.) is not a parameter here; if they are legal tender, they are coins by definition and you can technically pay with them at face value. Then, coin catalogue.
My own personal view is that government backed legal tender currency is not exonumia.
In my opinion anything issued officially should stay where it is otherwise we open up a bottomless can of worms.
If they are legal tender then they are approved by the government and should not be part of Exonumia,