This point reminds me. Can you buy eShop credit in usual denominations (i.e. will it solve the leftover points problem)?
Do you mean, are you able to pay only the exact amount required for a Wii Shop Channel game in the same way that you can for a 3DS eShop game? Don't think so. Using credit card/eShop cards on the Wii Shop Channel still forces you to buy in 1000-point increments, AFAIK.