IPCameras are just streaming a video file over the network, there is no Hz to speak of.. they dont include power converters and it takes DC power; which has no frequency and is the same wherever you live.
If it had an analogue video output it would need to match your analogue video inputs; there are a few cams here and there still with a analogue and IP output but they are not common, this is just crap left over from the analogue days.. some bureaucrat somewhere has a form that says all cameras ordered for the state of blah must be NTSC, meet so and so certifications and this and so forth.. one day they might disappear but expect to see the choice between NTSC/PAL for a lil while longer.
the labels are the only difference, relics from a bygone era