This is nice and Google themselves had an ad campaign that did exactly this. It will
work until Google decides to delete the email address for some inane reason. I guess that’s partly why they nixed that campaign.
Then, their Google+ architecture allowed random people not part of the family group to view said photos of people's very young children, and it got a round in the tech news cycle. They started tightening up the architecture and in the process decoupled it from the dying Google+ to go on to release it in 2015.