Been there done that:
Used anchor alarms in the past, but not anymore:
We sleep in the v-berth and just forward of the mast
A gale or a squall will wake us up before the alarm due to the howling in the rig and the wave action.
IF ya have a bad anchor and IF ya anchor over bad holding grounds, then by all means, set the alarm, or even better, set an anchor watch in the cockpit. (Usually yerself spending the night in the elements, it could however save the boat)
The secondary alarm is the depth-sounder:
It may not squak as often as a sensitive GPS when the boat moves, only when the depth
goes from 10 to 6 feet.
Or skip all of them alarms, just get a good and over-sized anchor, then set it with full power astern, then go to sleep...