you made it seem as 

CDs>MP3s 

The audio quality is better. That isn't opinion, since it barely uses any compression for the sound. That's also the reason some companies were reluctant to get in  on MP3 tech, since they assumed the lower quality wasn't the kind of thing people wanted (thus came the format war between Super Audio CD and DVD Audio... that neither ended up winning).

It's the convenience that makes MP3 better than CDs, since you can just pack loads of songs onto a player without using discs, and on the right player, you have even better ways to play the song you want.

One mistake, there is no compression on a CD (unless you count quantization/discretization limits). It's a raw digitization of a wave form.

so how much better is it?

1x,2x,3x...10x?

Yeah I noticed it too.  I like it better than the disc.

Ps3 has had that for a while. I am surprised to hear that the Wii has it since i don't believe the Xbox does.

Nice feature.  I never bothered to get the disc since I steamed Netflix through my blu-ray player. 

Hard to say precisely. The better sound quality of a CD will be effected by your speakers, sound card (even portable players have basic onboard sound cards), post processing and of course, your ears. If we are talking about 320kbps mp3 (which is what the scene releases usually are) the decoded wave is likely to only vary from the original CD by a few percent. (That said, I still get my rips in flac or buy the CD, and then encode it to flac.)

Lmao unless your mp3 is in 320kbps you don't know shit. Off to listen to my superior albums in flac

Wii's had it for awhile too, at least since June when I got my disc.  360 is getting a search function too now afaik.