Most digital cameras nowadays are quite powerful, anything from 7 mp and above is quite impressive to say the least. In order to use the full scale resolution, one must need sufficent memory, either on the cameras harddrive (which a few models contain), but the majority being some type, of external removeable memory card. In most cases a memory card is need, and thus unlike the 16gb which might not really work on most cameras, due to its extensive memory status, or even if it does work it might slow down certain features of the camera, but MOST cases an 8gb is more realiable and does not affect the camera's funtions.
All in all this is a really awesome memory card, for them high resolution shoots, and is worth every single penny! and its so cheap! :)