Well, the problem with it is that you'll have more than you'll ever need in less than a week of play. A proper currency should be useable in enough ways that you can't get enough of it.
That's true. At the moment, pretty much anything that changes your stat values changes Gearscore. Ah well, I haven't seen any real focus on gameplay balance or the ability to play with friends who get more time to game than you (2-3 levels character difference at most and even then, they will rotate out of dungeon and…
Get some better gear. 600 points of gear score isn't hard to improve, especially if you've got empty enchantment slots still. I could be misunderstanding your complaint, though.
Double-clicking the enchantment just opens the fuse window. You just need to have an item with a slot, right click the item and you can put the enchantments in, even if you don't have 4. Fusing 4 together, just makes a better, higher rank enchantment.