Another country straddling Europe and Asia is Turkey. United puts it in Europe for award purposes. That with Turkish Airlines’ great award availability (and superb IST lounge) makes a lot of Europe creativity possible. I am going through Istanbul to Malta and on to Greece later this month.
The flip side is that Turkey is a terrible transit point for Africa and Middle East awards, where Turkish has so many destinations.
Fly Africa to Africa via Istanbul and you get hit for 60,000 miles in coach, like this: