This strategy makes sence, but expect once in a while you will be left with worthless alt-coin, so dont buy back more coins than you sold, regardless of very low price
It's not much different than trading penny stocks actually. Most will become worthless or near worthless. Every now and then you will get lucky and maybe 1/2 will amount to something. Remember, there's usually a reason something is selling for 1 cent, or even less than a cent, it's probably worth it!