Let's say I have family photos from the past 30 years and I want to share those photos with my mother. The way you've described this implies that I have to have my mother organize tens of thousands of photos she didn't take into galleries and folders, even though I have already done all of that work. That requires the shared party to be both computer savvy and a heavy Photos user. What would be more useful for my use case is the ability to share galleries and folders and have those show up with the same organization and structure in her Photos app. I want her to be a consumer of the existing structure rather than a creator of a new structure based on my going through each album and adding metadata to the pictures to name the album and have her pull that specific metadata and create new albums on her own. That will likely never happen, but she would happily view something that I've already done.
Way back in the iPhotos days, I could share albums via a website (sort of like Flickr) where they can see multiple albums and navigate from there. That functionality was replaced with the current sharing options, but that doesn't present a site with multiple galleries that someone could navigate. I eventually started uploading pics to Flickr, but even that is a lot of manual work because there wasn't functionality to easily convert albums in Photos to albums in Flickr (you have to manually export the photos in an album, upload that folder to Flickr, and then organize those photos in Flickr into albums which is essentially duplicate work like the current shared photos feature).
So in conclusion, it would be lovely if there were an enhancement to the shared library to allow the sharing of entire folders and albums (not just photos within an album) with their existing structure for other Photos users, and an Apple version of a Flickr-type website where you could share a set of public galleries that are navigable from a public shared album home page for non-Photos users and Windows folk.
Thanks for your time if you made it through this response! lol