Those non-Gmail accounts also get threaded conversations, just like Gmail, which is a nice touch.
Were not seeing it in Google Play yet, its likely rolling out to all users slowly.
All Your Mail, Together in One Place| Official Gmail Blog
Gmail for Android Gets a Combined Inbox View, Better Search, and More
Android: If you’re tired of switching between your accounts just to see all your new email, Gmail has finally added a unified inbox view that shows al
