What difference does the ld,dp,and rs Make on SE stick?

Why even have the option and what difference does it make? I always keep it on dp and was wondering why I would want to put it on ls or rs?

Some other games might not support the dpad? I dunno.

I keep it on DP as well, and some retard gawking over my stick today at fight club clicked the switch when he lost a round, and when I got it back I got owned, had no idea why I couldn’t move and was about to order a JLF, when I realized that the switch can click over to RS and be useless.