Earlier quoted context omitted.
And that is exactly why, at least on Android phones, the out of box Plus configuration is to automatically upload all pictures that are taken on a phone.
You've got to have misstated that. That would be a complete and total disaster of enough scale to completely kill Plus.
When you load G+ on Android it asks whether you want your photos uploaded by default into a private album. It isn't the default by any means - the default is to ask the user what they want to do!
It works really well too. I took a few pictures with my device and not even thinking about it got on my computer to upload them, before realizing I had told my phone to upload automatically. Very easy experience to share my photos and videos this way.