Ehhh. I think if you're trying to show the overall costs of something to someone that conclusion makes sense, but interactive flame graphs are the best way imo to look into things. Especially making use of sandwich views, which allow you to pivot the flame graph around some function to see callers and callees by cost.

Edit: I'll keep this up to share my embarrassment, but I missed entirely that the article was about disk space. I admit I only looked at the pictures haha.