Good article in general, but it's odd they didn't mention DXA scans. Those are now the gold standard for body composition measurement and are fairly cheap in most developed countries.
Also seems to not mention that the biggest inaccuracy of BMI is that it tends to underestimate the rate of obesity (bodybuilders with the opposite problem are a rounding error in population-level statistics, many more people have very low muscle).
"For instance, Asian people tend to be at a greater risk of conditions such as heart disease at lower BMIs than are white people, probably owing to differences in body-fat percentage and distribution. The WHO recommends that Asian populations use lower BMI cut-offs for overweight and obesity, which several Asia-Pacific countries now do."
