In a very recent post here I recently learned that simultaneity has no meaning in general relativity; I can accept the answer and explanation that was given for that question.
But then Harry Johnston replied to my comment saying that the concept of simultaneity also has no place in special relativity - that it's just a pedagogical tool.
Is that right - simultaneity - what I take as two observers in separate reference frames not necessarily agreeing on when events happen, or even the order in which they happen - is just a pedagogical tool?
To what end? How does that prepare them for understanding general relativity?
I only have a cursory understanding of both SR and GR - but now I'm really confused.