Slipin Lizard, one thing I found from playing these games is that it makes you learn where the frets and strings are without looking down at your guitar. So in bandfuse the tab scrolls from right to left and on faster songs or more complex parts that I don't have memorized, I need to look at the TV screen most of the time and only occasionally glance down at the fretboard to make sure I'm moving to the right fret.
Another great thing is that I hated practicing with a metronome or sometimes using backing tracks got boring. I love being able to play along with a real song. Not only does it teach me how to play in time with other musicians, it also motivates me to play way more than I did before.
Lastly, when I would sit around and try to learn a song I would always go off on tangents after a while(I think we've all done this!) and loose focus. With the game going I stay totally focused on playing the music, because I'm trying to beat my precious high score. Or like in the Lick Lab, you pick a part of the song to learn and it starts it slowly and speeds it up as you play it accurately, and eventually it makes you play it 5 times at 100% speed before you can move. You need to be like 85% or 90% accurate for it to count. You can't just go off noodling around when it's having you play something for the 4th time in a row! Keeps me focused on the song!