The MFE DVD player ran in GameCube mode, which might be different than that of Wii mode, but the theory is that extensive use of the wii laser would eventually wear it out. This is true of ANY laser, be it PC, PS3, Xbox, a generic DVD Player, etc. The more often you use a laser the quicker it could eventually stop working. Watching a 2 hour movie on DVD is slightly more taxing then reading a Wii disc because the laser is on for the entire 2 hours of the movie, but your'e only reading it at 1x rather than the full speed a Wii disc would usually be read at. When a game doesn't have to read from a disc, it turns off the laser to save power more than anything, but it would also extend the laser life slightly. In all honesty, however, it really isn't that big of a deal. A wii's DVD driver isn't really any different than any other kind of DVD-ROM drive. They all eventually wear out one way or another.

In other words, while there's some truth to the whole "playing a DVD could wear out your drive" it's no more true than saying playing a DVD movie on a PC could wear out your DVD-ROM drive. It's seriously not something you need to worry about.