There's nothing wrong with trading Bitcoins, just like there's nothing wrong with exchanging USD to EUR to buy a glass of wine.
Yes, but if you are spending a lot of time or effort trying to make money on an essentially unproductive activity then I think you should ask yourself if there's something else you could be doing that would be more effective at making the world a better place.
I think a lot of buy-low-sell-high, there-is-always-a-bigger-fool, or high-frequency trading fits into the "isn't making the world a better place" category. If you're competing for a bigger slice of a fixed-sized pie, I think you should think hard about what you could do instead to make the pie bigger for everybody.
Mmmm.... pie......