My guess is it's probably more of a blood choke, while the double chinstrap/ten finger style attacks more of the windpipe. Id also wager a greater relative ease/simplicity of grabbing onto it and holding onto it. The gross motor movement also has some overlap with the power assist guillotine.
It could also simply come down to a habit of contingency. Someone learns doing it one way, and just keeps doing it as long as it works. I know the instinct for 'technique hoarding' can be pretty strong, and any time you learn something new you want to 'invest' in it somehow; trying to come up with an epicycling gameplan where anything and everything you've ever seen has a place in it in some way (even if taking a roughly contrary tack might ultimately be more practical).