Utilizing alarmd gives you a lot of very handy and awesome benefits compared to just setting the alarm within your app; from my understanding of it by using the alarmd interface:
- Your app doesn't have to be running for the alarm to occur. You can actaully setup the alarm to launch your app if you want, so that when an alarm goes off the clock app will open if it's not there already.
- Alarmd will continue to run and trigger events at all power states of the tablets. This is important as it relates to your power savings features. If you implement proper power savings when the tablet goes into idle (not used), your application should literally stop doing anything so that the tablet can save power; it's awefully difficult to keep checking the time and comparing it to the given alarm schedule though if your app isn't doing anything, so the only way to make it work would be to have your app continue to run at some level, which wastes power.
- Alarmd has the added ability to trigger alarms even when the tablet is "off" mode... that is, if you set and alarm and turn the tablet off, put the tablet on charge, the alarm will still execute normally. Good for those times when you have something like a daily alarm, and one night have your tablet off and forget to turn it on... alarm will still run.

I'm sure there are other reasons, but from my understanding of it those are the obvious ones. The biggest point, of course, is that whole alarms will still run even if your clock is not. This is a major point. Think of it this way... if you set an alarm, then do some other stuff on the tablet (surfing the web, reading an ebook etc) before going to sleep and forget to switch back to the flipClock, your alarm will never go off! If you implement alarmd functionality then in this same scenario you can make the tablet automatically change to the flipClock app (and even open it if you had closed it before), and handle the alarm as expected.