There is no reasonable 'benefit' to being in permanent AF....or knowing that you are in that cardiac state. There would be a great benefit from being free of the dysrhythmia, though. Your heart remodels itself over time and this can lead to other problems when you spend a long time in AF.

What I mean is, if you really ARE in permanent AF, and must live like that because no specialist deems your heart fixable for some reason, then knowing what your rate is might be the best you can hope for with a wearable device, not that you ARE fibrillating. I say this because the health field doesn't advise leaving heart rates above 100 at rest. Rates much above 100 signify pathology that could lead to heart failure....I mean real 'failure' due to exhaustion.

So, to your second question above, yes, someone who is new to AF should be aware of changes in either frequency of runs of the arrhythmia, their duration, or heart rate when they go into ANY dysrhythmia. The reason is that the heart will change, or remodel, itself to adapt to the different conditions. This could mean enlargement of the atrium, mitral valve prolapse, ventricular enlargement, and drastic changes in the ejection fraction as a result. Someone wearing a device that might alert them will help them to realize that things are beginning to slide downhill, maybe at a faster rate than hoped, and that they need to get in line for an intervention.