I think interestingly enough it’s inaccurate in the other direction. While BMI is will call people unhealthy if they have a lot of muscles, this will call people healthy if they are like me severely underweight.
My roundness index claims it’s in the healthy zone while in reality my weight is unhealthy.
I’m currently receiving treatment for onset osteoporosis caused by malnutrition. Also it’s kinda obvious your weight is probably not healthy when your ribs are sticking out.