It is not free storage, as the only items that can be put in are essily reacquirable ones, such as salvager items, which wouldn't need storing in the first place for that very same reason. That is why most people who expected it to be free storage are mightily miffed if you call it that.
It has some uses and it does well what it does. But what it is, is free an easy way to use armory items in your glamour. And a possibility to burn items you want to use for glamouring purposes. But that's not storing them as very definition of storing is to "keep something so I can use it later for whichever way I want".
The worst thing is that even the ingame help texts are rather misleading about how it work so people have expectations for it which it doesn't fill and understandably are angry it doesn't deliver what it alludes to.