Casper's biggest selling point for the Glow light it that it will help you get better sleep. The main two ways it says it can help you sleep is through its warm, attractive light, as well as through an automatic dimming cycle. When you turn it on, by default it slowly dims for 45 minutes until it's off. (You can change that time setting in the app.)
Ultimately, though, I chose to continue to do stuff like read my phone in bed, which I'm sure ameliorates any of the benefits of the dimming light. When I read using the Casper Glow, the dimming light didn't lull me to sleep — it just annoyed me. I would have to adjust the light to keep it bright enough to read. Ultimately, I would turn off the light by flipping it, and then try to fall asleep the way I've always done.
It can also be used as an alarm. Through the app, you can tell the light a certain time to turn on. But I preferred my window and daybreak as a gentle way to wake up.
I did have one amazing night of sleep last week — but I don't think it had anything to do with the Casper Glow. I simply made the choice to go to bed early.