Currently Playfab talks a lot about item stacks. They're no stacks though. It's actually an item and it has an amount. A bit like "uses left" in v1, just easier to handle. Once you understand that v2 is actually like this 
it becomes much easier to understand. Suddenly I know how to handle item instances and what to do with stack name, which is really more like an item instance ID.
You're probably going to say "Oh but it's stacks of items and we always used the term stack". Well, no. They're not stacks of items. If I have 10 Barrels I don't actually have individual unique 10 Barrels. It's 1 Barrel with an amount of 10. If I want to label each of them individually, I'd need to create 10 item instances. Makes sense when you talk about item instances, but having to make 10 stacks of 1 is a cumbersome thought process that not everyone will find intuitive.
I hope this helps to make Economy v2 better.
