Several threads on this if you do a search. Most of them ask the question "WTF do you want to do this?"
nothing wrong with having a b/up dvd player, u need to install t/light hack, then dvdx, then load up mplayer off sd card.
Reasons for not playing DVDs on a Wii. 1)A Wii is expensive, a DVD player is not. 2)DVD players are easy to find. Wiis are not. 2)Playing DVDs subjects your Wii to a constant ON duty cycle, which adds to wear on the DVD drive/laser, thereby shortening the life of both components. 3)The Wii suports only 480p max, and makes a mediocre (at best) DVD player. It may make sense to you, and if it does, great. It doesn't make sense to me.
well as i said "backup" if yr normal dvd player goes down yr stuffed till u can get your self a new one, but if u got the wii as one hey things to watch till one arrives.