To me it's just what the folder is called, unless I'm missing something?
Yep, you're missing something. Camera roll was a simple grid-based view of all your photos (like Recent, but with all your photos). The "Photos" tab is all your photos categorised into events using a "smart" algorithm (time and location based). The problem is that this sorting isn't always so smart. On an iPhone 5 the normal grid view can fit 20 photos on the screen. Yet with categorisation in Photos, quite often you only get one photo in each "event". Events are automatic, you can't move photos around, so you're stuck with the way it categorises the photos. Maybe not a problem to you, but when you have thousands of photos (I have 4500), it actually makes it extremely frustrating to scroll through your photos. Example below, Camera Roll would show 20 photos on this screen, yet Photos shows 3.
I don't care if it's called "Camera Roll" or "All Photos" or "Disable Categorisation". I just want the ability to see all my photos in a simple grid view, and that's what Camera Roll used to be. I'll be glad it's back, and you'll just have an extra folder in Albums (that you can ignore if you want). A win for me and no loss for you, everyone's happy.