Unfortunately, I have to hope this doesn't see widespread adoption. If this becomes the standard it will just add to already existing social pressure to get an iPhone in the US.
> anyone can RSVP, regardless of whether they have an Apple Account or Apple device.
But no-one without an Apple Account can create them - you can only respond to Apple-having friends. There is social pressure in that too.
A company creating a useful tool that encourages people to buy their product is incredibly boring, typical, and not at all controversial until it's Apple doing it.