Would be great if the confirmation email for an appoinment / event contains a link / button to add it to Google Calendar.

Sure, the OA user can sync his/her own calendar with OA, but a lot of times you have to forward the appointment to someone else, or want to change details on the appoinment and OA Calendar doesn't allow you to do (I'm aware there's another suggestion about that).

We presently duplicate the OA event and then add details to the duplicate event and then share that via GCalendar but... why making it that complicated?