Sure, night dives can be a little disorienting at first, but as others have mentioned, that's when a lot of sea animals come out of hiding. On one night dive I did in Mexico, I saw my first live crab ("Quick, someone grab dinner before it gets away!"), several lobsters, and two massive turtles that must have been close to 5ft long from head to back flippers.
And on my most recent night dive, I knew my photographer buddy would be busy taking photos, so I took on the tasks of navigating and air & time monitoring, and managed not to get us lost, LOL! During that dive, we saw SO. MANY. EELS! And lobsters! At one point I signaled to my buddy about a cute baby eel poking its head out of a crevice, and he pointed down urgently; right in front of my hand were two lionfish (oops!). And the best part of that dive was the end: on our way back to the boat, we came across a partially eaten fish carcass on the seafloor... a reef shark swooped in from the darkness over my right shoulder and proceeded to eat it just 3 feet in front of me. Oh, if only my buddy could've gotten it on video!
Definitely invest in a good light and a backup light. Make sure you dry them off well after the dives and, equally important, test the lights before each dive! I found out on the boat before one night dive that my backup light wasn't working, a bit late to learn that! It could've been dicey if I'd lost my main light too. I'd also recommend a strobe light to attach to the boat's exit line or to place in an exit spot for easier navigation, and a colored light stick to attach to your tank: if you and your buddy are on opposite sides of a coral patch, a light stick attached to your tank will let your buddy know where you are and help the two of you not lose each other.