Yeah people are encouraged to hold the coin, but as you can see not everyone is gonna hold it as they are not obligated so I don't see the points of you argument where you claim that if you don't spend a coin it is whorthless: since you are not obligated to hold, the coin is not necessairly worthless. Much logic? Oh and by the way, holding a coin forever is just not profitable since at a certain point it will be more profitable to sell than to hold even if you get some interests. (And thats obvious since if you are not going to spend a single mint in your entire life there is no point on getting the interests lol)
All you say are mehbeys and future. You can not back them up with more grounding than I can my claims about ecomomical logics what a currency needs and why bitcoin and more relatively unknown small clones like mintcoin won't stand the race in the long run. They still claim to be currency while they try to mimic virtual gold.
No one needs to hold gold but everyone would fill their rooms with that, if gold hadnt more purpose than laying there in shiny bars. Same goes with all other goods that have a certain value. And there is a reason why people pay with papersheets and not with gold coins anymore.