One might have assumed Susan simply took the sudden appearance of wings and a halo in stride.

One would be mistaken.

Semantics! HOORAY!

This is not change blindness. Or, at least, it is not "officially" change blindness.

Change blindness is an actual phenomenon in which someone cannot tell something has changed because they did not see the change happen. This can refer to something like an object appearing or disappearing, or not noticing that someone's shaved their mustache.

My (extremely limited) understanding is that our minds make use of certain shortcuts to process visual information based on our expectations, and those shortcuts sometimes result in us missing things, up to and including someone we're talking to being replaced with another person (such has been done for giggles and science).

I'm not sure what I'd call not noticing one's own physical transformation. Morph unawareness? Change obliviousness? Fred? It's a puzzle.

It can be argued that "change blindness" is a valid way to refer to this, even if it has a different, more specific, real world meaning. I just worry about confusing the matter of the actual phenomenon, which is incredibly fascinating all on its own.