This is one heck of an exciting card to be sure. You probably would think its applications are rather straightforward, but let me assure you they are not.
You see there is still a point AFTER you have dealt combat damage with your creatures that they are still considered attacking. I mentioned this a while back in my Maverick article. The trick was with Maze of Ith which gave your creatures pseudo-vigilance (usually to a Knight of the Reliquary)
What does this have to do with Aetherize? Well, you see…if you play a lot of ‘enter the battlefield’ trigger creatures much like everyone does in the current Standard metagame, you might want to do this. You can get insane value off of your Thragtusk, since you get a 3/3 then recast to gain 5 life afterwards. Or it can just be a great way to play around cards like Supreme Verdict as well (by returning not all creatures, but the ones that you can recast for value while retaining a good threat and forcing the Supreme Verdict).
Gain even more value with Snapcaster Mage too! Any whacky scenarios you can conjure up are sure to be reasonably good.