If you do find such a thing, bear in mind that it will probably have little or no security and could be controlled by anyone within range. A range which might be anywhere in the world due to the current fetish with connecting things to the internet. At best, it would be unreliable. At worst, it would be a means of accessing other devices on the same network.
I can think of 4 reasons:
1) To use the alarm on someone else.
2) To use the alarm clock as a means of making something else happen.
3) For some reason their phone alarm doesn't work for them.
4) To get an insecure device onto a network.
