I feel the "ideal" use of this method would include assistance to ensure that the bag stayed on. Looking at how it works, how quickly it starts to work, what can go wrong (especially without assistance), in my mind there is too high of a likelihood of ending up still alive but with brain damage too severe to allow further attempts.
Aside from that, I have the impression it is rather expensive and would require much too much effort from me considering that a) I might not be able to get it working at all and b) even if I did get it working I could fail and end up severely brain damaged. FOR ME, this method would only be usable if I was in a situation where there could be outside assistance in carrying it out, and if I had technical assistance, e.g. if I was able to buy a kit that was pre-assembled by an expert or had the whole thing laid out for me with diagrams, detailed written instructions, and a list of the EXACT (by brand and part number) components that I would need to buy.
TL;DR: the mental calculus factors in my personal physical, mental, energy, and financial capabilities.