I think all kids should go. Most will have a chance to win a match on the backside if nothing else and it give lower kids a chance to see what that higher level is. I believe there is also benefit to greener kids to see how kids prepare and act in a big tournament like this. Have your kids watch how top kids prepare, warm-up, drill, take a loss, etc.
Many, Many state champs, etc will be beaten at this tournament. It's a great tournament not just for the top kids but for everyone. I have also seen some "greener" kids get a big win at this type of tournament and it makes them catch another gear.
JMO