Good point. If south-up were the default, we would probably be manufacturing globes without any mounting system, and just leave them lying around with the Eurasian landmass facing down due to gravity.
It's true, that's how Weebles wobble but they don't fall down.
Also if the map is flat on a table, more stuff is closer to you.
But if you pin it to a wall, it's easier to reach the top pins with the most earthful bits at face height if the earthful bits are at the top.
No no no.
We should put Asia at the top, Europe bottom left, Africa bottom right.