however scarcity is possibly the least useful argument for explaining why bitcoin has value. There are only two keys for the locker under my desk - making them much much rarer than bitcoin - they are however entirely without value as the locker is empty.
True, supply is nothing without demand, I found this out in the antique and collectibles world where you may have some really rare piece but if no one wants it it is just a big paperweight. But if the demand exceeds the supply then you can expect what will happen.