Duolingo really should have more items available in the lingot store.
If you want lingots according to your other discussion, why are you complaining about your options to spend them? They're pretty useless unless you want to give them away, which I like doing, but have none at the moment. I spent big and gave lots away too. (I don't give away lingots to requests, just good comments etc..
After buying the new items they add, wouldn't you be in the same situation again?
It seems like we're either going to end up with excess lingots, excess items in the shop that barely hold your interest for a few seconds, or no lingot system at all. If there are excess shop items, there will be more begging for lingots on the forums and more developer time spent setting up the new shop rather than working on other features that probably have a more direct impact on the learning process.
You could think of your lingot count like you do your level and streak: rather than wasted potential, something to be proud of.