Have in mind that a few number of games aren't compatible with emulated memory cards, so it's always useful to have at least one around. You can check the Nintendont Compatibility list to see which are not compatible!
I don't have much more to share about the subject (although I agree with alexander1970, making backups to preserve the discs and the console's lens longer is always worth it), but here's another nugget of information:
One BIG advantage of using Nintendont, even using physical discs (thus meaning you can just play them "the normal way") is that, because Nintendont runs games on Wii Mode, it takes advantage of the higher processing power, which results in better performance, or in simpler terms, better frame rate.
The difference can be pretty damn amazing. Sometimes it helps that little bit the original games needed, like Sonic Adventure DX, in GC it loses frames and it's around 50~ fps most of the time during gameplay, but it's 60 smooth with Nintendont. Other times is like black magic, like with TimeSplitters: Future Perfect. Instead of doing 30~ with drops, it skyrockets to 60 and stays there really well.
