This is what makes Anaheim such a good trade partner IMO. Skinner doesn't need to be the starter there, they have Dostal for that. OTOH, they have zerrrrro good goalie prospects beyond that. Their closest is a 21-year-old with a 2.92 GAA in the AHL. Everyone else has comically bad numbers no matter what league they're in or how old they are.
Dostal + Skinner has the potential to be a very good tandem for a lot of years and maybe under a different goalie coach Stu finds another level. Gibson doesn't help them address the future, and will go back to being a boat anchor of a contract if this season turns out to be a mirage for him. So why not flip him for picks and a younger backup-type if you can? It's a no brainer for both sides.