My wife has had four H-D and I have had three. All had a "kill" switch and an ignition switch. All could be shut down by either. Does it make a difference to the bike? No. On EFI bikes the fuel pump is controlled by the "kill" switch. So, if you want to turn on the ignition without turning on the fuel pump, turn off the "kill" switch. Also, as some posters have pointed out (too many pages, too many posts), using the "kill" switch to shut off the bike invites forgetting to turn off the ignition (and headlights, taillights, etc.). I see this happen all the time.