I think taste builds up a tolerance to sweet in the same way it does for heat. I used to drink lots of soda, but I stopped drinking it completely and now when I have a sip of Coke it tastes WAY too sweet and I can barely stand it. For people who eat lots of fast and ultra-processed foods packed with added sugar, salt, and fat, they need more extremes like this shake to overcome their tolerance in the same way a person who eats lots of spicy foods gets bored with jalapenos and needs ghost peppers and Carolina reapers that would destroy most other people's palettes.