They may help with this but they are not a solution...look at it this way...
You get shrimp...they eat your aptasia...then, the aptasia overrun what your shrimp can eat and you have to get rid of the aptasia anyway...
Or, your shrimp live mainly off the aptasia for a while...then, one day the aptasia is all gone...what will they eat now?
Things like Copper Banded Butterflies and shrimps are good treatments for aptasia (and many people use them with great success) but the only true, sure-fire way of solving the problem of aptasia is to get rid of them early in the game...this is one game you definitely do not want to get behind the 8 ball in any way shape or form...if you lose the battle with aptasia early on you may not recover very easily...