My two cents:
If you're a pitcher, a showcase is not always all that helpful. Do a couple WWBA tourneys and PG will have all the data it could ever need on you. Exception: If you get invited to PG National, don't miss it.
For offensive players, a WWBA event can be a tough place to shine. A showcase is smart, so that someone can study your swing, see your fielding actions, RADAR gun your throws, time you in the 60 -- all things that don't happen so much in games. Still, they need to see how you are in game action, so you have to play in tough tourneys too.
I love the WWBA events for sure as a vehicle. You can't do that all summer or all fall, but you shouldn't miss them as part of your schedule. Offensive guys should add a showcase, but to me, pitchers don't really need to.