As I said, bitcoin mining is not profitable using video cards anymore, you can try just for fun though.
I switched to litecoins, because it is 2.5 times more profitable. Then I exchange litecoins to bitcoins. I just wish I switched earlier. Lost a lot of time mining bitcoins. Still my video card is not completely paid of.
Erupters can not mine litecoins. Video card can.
Erupters can not do anything except mining, and good luck to sell it when it become not profitable. Video card can be useful in games and you can also sell it if for some reason mining would be not profitable anymore.
for all intents and purposes 2.5 Times 40 cents is still only One Dollar.