I don't think this store refreshes - It's once per episode. It seems likely you will be allowed to keep the currency between episodes though.
If they raise the cap, that would means you could collect enough currency to last several episodes (ie, you can skip buying the pass for future ones) if all you care about is buying omicrons. I don't think they want to give you that option.
They probably could add more different loot though, but perhaps their idea is to give you gear for scavenger relic mat conversion, like some of the raid and guild currencies already do. Are you able to empty the store if you collect all the currency with the episode pass?
I'm not saying things are great. I'm just pointing out potential reasons and problems.