>The point in time is a data point (on the time axis, if you will)
You need some way to place in on that axis, though. Commonly we use Day, Month, and Year to do so. But we could also define a date as the seventh Wednesday in 2019. Or as an integer relative to Jan 1 1970.
FWIW I'm struggling to come up with a good example of where the line between data and functions is clearcut, except perhaps when the data describes a function: an SQL string, some code that'll get eval'ed, etc.