Nightmare said:
it's better that way, because pal games are generaly slower than those on ntsc...
A lot of DC games had a pal60 option (Which technically is superior to NTSC, higher res and the frame rate).
Games didn't have to be slower at 50hz check wipeout2097 50hz version and 60hz version run at identical speed (Not frame rate). Wipeout2097 was programmed in Liverpool so the english coders bothered to optimise the games for the UK market most developers really couldn't be bothered (Nintendo I'm looking squarely at you) so released Shoddy conversions with big black bars (Because NTSC is lower res than PAL, a lot of developers just cropped the game instead of taking the time to convert it) and slower game speed (Just ran the game 17.5% slower rather than taking the time to do a proper conversion.)
I'm no PAL or NTSC fan boy RGB is much better (Don't think you yanks have it might be wrong)
One last thing although NTSC runs at 60hz (which works out at 30 frames a sec because TV is interlaced) Film in the flicks runs at 24.something frames a sec without anyone noticing so I don't think the extra frame rate makes much difference.