It’s tricky,

It works well at a population level, and the reality is that most people with a BMI indicating that they’re overweight are actually overweight

It doesn’t account for muscle, bone density etc.

I have visible abs, but my BMI is overweight. It’s because my bone density is unusual. I sink in water, and I have muscle

I also am middle-aged and have some fat that I didn’t used to have

People like to write BMI off because it tells them something they don’t want to hear. Everyone refers to athletes and the like, and I’ve upset plenty of people by saying “so, you’re a professional rugby player, are ya?”

It’s not perfect by any stretch, but it may give you something to consider

I have had people describe me as “skinny”, when I’m definitely not. Especially Americans

Most people are so used to seeing fatties that a healthy person looks thin by comparison