This is a premium proof set! The difference being all of the coins in this set are bright without any haze or cloudy coins. This happens when being able to choose each coin for assembly, not a random set with 1 or more inferior coins. Now we have a set of premium coins, next we house them in an archival safe Capital holder, usually white because the light is drawn to the coins. Next metal screws are used to secure the coins in their holder, not the cheap plastic ones that break when you try to tighten them.
Last, the set comes with a display box that has a clear lid for viewing without having to open the box. You will probably be able to find a "cheaper" set, but then that's what you will end up with!