You are definetely right but let me just comment about the physiological exception.
In the in the case of this blog post the might actually be some differences. The writer may really have some genetic problem in his/her circadian clock. Sleep is known to be under regulation of two mechanism: a circadian mechanism (about 24 hour for most of us) and a homeostatic mechanism. It is known (it is actually one of the few things we actually know pretty well about sleep) that the NREM is under control of the homeostatic mechanism while REM is under control of the circadian mechanism.
The blog author has a longer cycle and it is likely that his/her REM kicks in later on in their night, therefore being incompatible with obtaining enough REM. By doing polyphasic he/she might be able to compensate for that.
In the in the case of this blog post the might actually be some differences. The writer may really have some genetic problem in his/her circadian clock. Sleep is known to be under regulation of two mechanism: a circadian mechanism (about 24 hour for most of us) and a homeostatic mechanism. It is known (it is actually one of the few things we actually know pretty well about sleep) that the NREM is under control of the homeostatic mechanism while REM is under control of the circadian mechanism.
The blog author has a longer cycle and it is likely that his/her REM kicks in later on in their night, therefore being incompatible with obtaining enough REM. By doing polyphasic he/she might be able to compensate for that.