this item is Bitcoin inspired project, with a 9 months perspective I still find bitcoin branded real world items cute. nice.
the golden era was February with some excitement up to May. period of lack of interest June to August caused delay in the post stamp project but now it has been done once. i opted for a re run to see if the idea gets again some attention. goal is to serve 20 to 50 stamps and quit or take timeout. been there, done that. try something else.
stamps as money seem less practical as bitcoins though. someone in this forum bumps on occasion 20 us 'forever' type A stamps. either they can't sell or he has plenty. Stamps to be redeemed must be physical delivered or used to send a letter (contrary to bitcoin).
As part of my research I tried to use bitcoins in exchange for accepting goods and services aka spending. be it content (electronic print media, donations to site operators, goods delivered via mail - guess what, p.ex. memory chips and second hand notebooks.
And their dominant use is postal service. they are pretty useless in other parts of the world (list of available practical applications approaches null).
Easiest way if delivering a post stamp is to glue it on an envelope or post card and use. if you want to round up the stamp price in bitcoins, i can add some worthless banknote from African or Asian countries. or a paper printout of the 12 pages paper that started this project.
or a folded sheet of paper size A4 (p.ex. for origami)
other more noteworthy (or obvious) defect of stamps in comparison to bitcoin is that they can not be divided into usable separate units and bear manufacturing costs.