No, there really isn't a reason to use it. It looks pretty, and I have to admit that's basically why I bought it in the first place.

It's easier to turn off in a false alarm. It can warn you ahead of time when the batteries are getting low. It can alert you over the internet if your house is maybe on fire. Not sure if that's worth the price premium, but there are some benefits.

There's a difference between "there's no benefit at all" and "the benefits don't outweigh the downsides." There are many benefits of the Nest smoke detector. Easier to test. Easier to silence a false alarm. Less likely to wake you up in the middle of the night with a battery warning. Built-in night light. Integration with the thermostat home/away features. Notifications of an alarm when you're not home. Easy identification of which room the alarm is from when you have multiple interconnected alarms. Etc., etc., etc. Now, are those benefits enough to justify the cost and to outweigh the problems? I dunno. Do you care about those benefits? It's up to you. But there are clearly benefits.