My lo was the same way. We used both kinds- straw cups and traditional sippy cups, some with rubber spouts, some plastic. It didn't seem to confuse him at all. I think it helped him get the idea that he was taking a drink.
We also played the game where we'd (I would do it mostly) move the cup up and say something fun like "whooooooop", make a sipping noise and then an "ahhhhhhh" noise. Not the best table manners- I know, but now it is funny because after all of that modeling and me doing it for him, he does it by himself and it is sooooo cute.
BUt I have not heard a reason to not use the straws, and we made it through alright using them.