Seeing this reminds me of the question: "why do we have an <img> element? Why not an <icon> element? Or an <include> element?" [1] Back in the olden times shipping a feature like the `url(path:)` above was enough to have it become a defacto standard!
Meta: link [1] uses text-fragments [2] that seem super useful to me but apparently are not implemented by Firefox (yet!)
Well, we have plenty of images already: <img>, <picture>, <figure>, <object>, <iframe> can be used for that purposes too. It is just unclear how <icon> is different from <img>.
As of <include> (so called client side includes) Sciter has them [1] as they make sense in precisely desktop environments - when files included from local sources (synchronously).
Especially for the Sciter (and now Sciter.JS [1]) where we can use SVG paths directly in CSS as vector images:
More details are here: https://sciter.com/lightweight-inline-vector-images-in-scite...[1] Sciter.JS preview: https://github.com/c-smile/sciter-js-sdk