Unlimited full-resolution photo storage is the main reason I subscribe to Prime.
Prime Video I could easily do without, Prime Music I haven’t even tried, Twitch Prime throws my friend a couple bucks a month, free shipping doesn’t matter since I could just wait to hit the minimum spend for free shipping. All nice to have, I guess, but I wouldn’t pay for.
But the unlimited full-resolution photo storage alone is worth the full subscription price. I don’t even know how many 100s of GB of photos my wife and I have taken over the last decade, especially since having kids. Maybe another 5GB/mo?