I tried both, and found the pictures with my camera were much clearer. Even those are not always perfect, coins are tough to do.
If he does decide to go with the scanner, Kimbo's suggestion works well. Put four at a time on the scanner, then use a photo editor to cut them out individually. That works well for stamps, should for coins too. They have to be reduced before they're loaded to eBid anyway, so it doesn't take me any more time to prepare them after they're scanned, and it cuts down the scanning time.