Multiple Date Formats

I’d like to be able to use YYYY-MM-DD / hh:mma when I have a specific appointment time but I don’t want to see YYYY-MM-DD / 12:00am when I have an all-day event.

I think this is the issue at Custom date format to hide time if 0:00am but I wanted to elaborate a little to illustrate the usefulness.

A custom #yyyymmdd type tag would not work because it would not sync with google calendar.