Both really work out and give you the exact same results in most cases. Devil's in the details though. Composition generally* works out better if you don't > have a fixed/known understanding of the entire domain.
If we had to add a new animal that had never existed before... like a Furry. Which is not feline but can meow is also warm blooded and also eats.
You know, it’s tough to write a web browser. Your browser is expected to display divs, log every click for ad targeting, and also render favicons. To render favicons you rely on the HTML supplied by web pages. Unfortunately, web developers (like me) are incompetent. Not just the little guys, even top tech companies can’t get their HTML right.
Youtube says their icon is 144x144, but it’s 145x145.
Twitter says their favicon is an image/x-icon, but it’s a PNG.