There may be a couple of advantages to being able to trade him prior to June 30.
For teams that are both trying to maximize cap room and trying to win now, like Miami, Gomes would represent a good hedge bet. If you get signals you can sign a major player if you free up a few more million, you can cut Gomes. If it looks like you'll strike out a bit on FA and won't end up needing every single dollar of cap space, you can keep Gomes as a useful player and claim that was the plan all along. Teams like Miami need flexibility + roster fill.
The other advantage would be that the Wolves won't officially have any cap room until after the draft, right? Because the 09/10 fiscal year won't be over yet? So on draft day the Wolves don't have any cap room to make deals. Gomes would represent a smaller slice of "free cap space" available right away for the receiving team.
This has got me wondering which teams would give up something we value for Beasley on draft day. Gomes to Miami, Beasley to Location X, Player/Pick to MN.
"It's tough to make predictions, especially about the future." -- Yogi Berra