Honestly? I agree with you that the benefits seem kind of marginal. But I still think it’s a fascinating thing. :)

Edit:

On doing some reading about it and trying it out for myself, the file size reductions are hardly marginal. It’s actually quite impressive. Still, it seems for most people, including myself, that jpeg for lossy & png for lossless is more than adequate, especially with how cheap storage is nowadays.

(And, frankly, I appreciate seeing at a glance if an image is lossy or lossless, but I imagine that’s a priority most people don’t have. Lol.)