HELP, I don't understand

Hi

Can somebody please explain to me why half of the San Marino coins classified on Numista as circulating coins were only issued in sets and therefore (in my way of thinking) are for “collectors” to buy and were not issued for general circulation.

an example

N#11835

thanks, Merv

If it's  set only then it can't be a circulating issue they are even sealed and most likely not sold at face value. 

so why are they listed as circulating?

That you have to ask the person that entered that specific data. But you can submit change requests to change them.