Because PAL games only need 50fps to reach 100% while NTSC needs 60fps. Or is there a catch to PAL games?
For games that run at 50FPS rather than 60, yes. For wii games, make sure to uncheck EUR60mode, then.
For PAL_NTSC games that run at 30FPS like Wind Waker, there's no difference of course .
And then there are some GC games that if you hold 'B' when booting it will ask you if you want to 50 or 60 Hz