This sounds a bit redundant; currently, we get 500 Potterpoints for winning a tournament, which we can spend on gold, XP, or store items. Adding a completely different currency would not really serve a purpose as what you're suggesting does pretty much the same thing that Potterpoints can do. Regarding what you said about staff wands (Such as the Builder Hammer, the GD Paintbrush, etc), these are only given to the people in that respective department. It's really a small token/perk of being in the department; being able to buy it wouldn't be fair. With the Crowns, if you win you (temporarily) gain access to the PVP crown for the rest of the month.