I have a digital photo library dating back to 2000, and I am basically the photo keeper for my whole immediate family. I don't use iPhoto, and I maintain my folder structure by year for every photo taken the last 15 years because not my whole family uses mac. I prefer the standard folder structure over being forced to keep an iPhoto library I can't control easily on a Windows PC. Being able to upload my phone pictures to the cloud and then delete all of the pictures off of my phone makes it easier for me to personally track my pictures. I download the latest phone backup off the cloud and store it on my computer in a folder. Not being able to clear my phone storage makes the process confusing for me, and it scares me that I would make a mistake. I do not consider the cloud a 'device' so if I delete something from a device I don't expect it to disappear from my backup service. This is literally how every backup service has worked, but Apple changed it up and it's nice for people who like it that way, but I wish there was an option to do it the normal and old way like every other cloud/backup service. It's a common criticism for people who don't want to be locked into Apple's folder structuring because I'm not sure I'll be using macs for the rest of my life even if I have been the last 10 years.
Hopefully that makes sense.