A:AnswerYou should be able to. PC USB voltage is a pretty universal standard, capping out at 5V (but rarely reaching that). It will have an effect on your charging speed and possibly, over several months of charging solely on your PC, the longevity and lifespan of the battery. But these batteries are easy and cheap to replace so no big dealio.
A:AnswerNo it is only a charger cord. It is good if you have damaged or lost the original charger that came with the ds or if you have a portable battery charger and need to charge it while on the go.