What are Keys used for?

I am getting a lot of keys, but not sure what they are used for????

Hi Teddybear

You use the keys to unlock different items in your room. Each item cost a certain number of keys.

I've already opened all the items with keys - the upgrades for each item doesn't take keys only shards or money. Is there something else the keys are good for other than selling?

Teddybear...........Welcome to the Forum! We think in future updates there will be more things to unlock with those keys. Save them up.

I have stopped with Trinas quests for now - untill we know there is an update/upgrade down the line.
I am saving shards to open more room items (allthough 1500 per item auch).