The problem with the Photos tab as an alternative to the Camera Roll is that is also includes all my photos in albums I've synced on my phone (and interestingly some photos I have on my iPhoto on laptop, and not synced to phone).
I would prefer the separation because if I go looking for photos I know I've taken on my phone, I now need to trawl through all my album photos too ><
Like I said: in this new system Apple disregards all of that. A photo is a photo is a photo regardless of source because they're not supposed to live on your desktop or laptop or whatever. They're supposed to live on Apple's servers.
And then there was the celebrity nudes scandal and they pulled the part where they house all your images. Amazingly that's what it took to wake them up to what an utterly idiotic idea it is to expect all their customers to give them all their photos.