This Alarmclock respect yours sleep cycles, in order to do a happy and healthy wakeup during your last light sleep phase.
This can be helpful for several sleep disorders like:
narcolepsy, hypersomnia, apnea, insomnia, etc.
Waking up in the middle of a depht phase or REM phase, is not good for your working, procedural and declarative memories.
Have a happy rem phase and dreams!!