During money shortage, stamps were often used as currency, so the proposal make sense as it's very close to numismatics. In fact, in some countries like Spain this is the same mint that produce banknotes, stamps and coins.
So for me, I see the idea relevant, where I struggle to see the benefits is that in general stamps collectors are less and less you can guess it seeing at the price of stamps over time. Colcnet database is about 1 000 000 pages for stamps, so the amount of work compare to the benefits is too low for me, but I will not vote against this idea just because I see it difficult. I respect the stamps collectors and would like to see them express their need or not to organize their collection and swap through our Numismatic platform.