Yes, it's definitely worth it. Snow levels are getting a bit low by August but the shred is still super fun. The public park should still have a few jumps up as well as a bunch of rails.
If you can postpone your trip by a week or two, the public park actually gets way better from the middle to the end of August, like after August 15. That's when High Cascade Snowboard Camp closes for the summer, and the public park gets to take over their terrain.