Notably, it shows how it's possible to use different images based on a portrait or landscape layout of the viewport, which OP doesn't cover. That's not always useful but it's good to know it's there when you might want to use it.
I was recently (well, several months ago) tasked with improving the Google PageSpeed scores on mobile for a site which has a lot of image-heavy pages. The end solution involved adapting all images to use a <picture> image with a WebP alternative for browsers that can show it (Google's tools like it when you use their near-proprietary image format; go figure), plus using srcset and sizes (which can be used on <source> tags inside of <picture> tags as well as <img> tags) plus a script which resizes and caches resized versions of large images based on URL parameters (basically an ersatz Glide [0]; I wish I had known it existed when I started). The end result severely reduced page weight for mobile visitors and was successful in raising our PageSpeed scores and appeasing my client.
Notably, it shows how it's possible to use different images based on a portrait or landscape layout of the viewport, which OP doesn't cover. That's not always useful but it's good to know it's there when you might want to use it.
I was recently (well, several months ago) tasked with improving the Google PageSpeed scores on mobile for a site which has a lot of image-heavy pages. The end solution involved adapting all images to use a <picture> image with a WebP alternative for browsers that can show it (Google's tools like it when you use their near-proprietary image format; go figure), plus using srcset and sizes (which can be used on <source> tags inside of <picture> tags as well as <img> tags) plus a script which resizes and caches resized versions of large images based on URL parameters (basically an ersatz Glide [0]; I wish I had known it existed when I started). The end result severely reduced page weight for mobile visitors and was successful in raising our PageSpeed scores and appeasing my client.
[0]: https://glide.thephpleague.com