This is a great illustration of the problem G+ had; events in g+ were amazing but nobody (apparently) knew. Setting them up was easy, inviting people was easy, privacy for events made sense from the UI, etc. If you set things up correctly, everyone who was invited would have a shared photo album that they would be able to share pictures to with one click.
I have a friend who had an amazing wedding photo album created this way; to this day they swear that if it had been marketed better g+ events would have put wedding photographers out of business...
Did people have to have G+ accounts to receive invites? I know Facebook requires it, but if they just used standard calendaring events (maybe with an info link to g+?) that would seem a winner
Maybe they added it later?
When it launched there was no such feature, I think they added events after a year or so, but by then all the hype had already died down.
I have a friend who had an amazing wedding photo album created this way; to this day they swear that if it had been marketed better g+ events would have put wedding photographers out of business...