Many people like night diving because different animals come out. There are lots of cool critters and behaviors you won't see during the day. When we dove locally I actually got to prefer night diving over day, since I wasn't frying in the sun in a wetsuit and often there was more to see at night. And it's not like you can see all that well on most daytime dives around New England anyway.
It can be more challenging/scary/whatever for many people at first, but it's really just another set of skills to learn and you can get over that if you are so inclined. It's true that not everyone night dives. At your typical warm water resort or liveaboard, you will have a fair number of people that don't like it or simply aren't interested, some that go occasionally, and some that love it and go every chance they get. For me, it depends how good the night diving is someplace, vs. how tempted I get by a drink with dinner, or bed.