I have noticed that you can still publish apps even if the workspace isn't listed on premium capacity.
What benifit/cons does publishing an app that's not with premium capacity have?
What are the benefits of apps on premium capacity?
Below are the advanatges of having PBI Premium:
So publishing an app for a WorkSpace on premium capacity basicaly gives you the above benefits, opposed to these being absent for apps for WorkSpaces based on Shared Capacity.