Yep, the underlying mechanics have to do the same thing - just swept under another a different rug. I imagine the (potential) advantage as being similar to when we had to do the same thing with JavaScript before promises came along. You would make async calls that would use callbacks for re-entry, and then you would need to pull context out from someplace and run your state machine.

Being able to write chains of asynchronous logic linearly is rather nice, especially if it's complicated. The tradeoff is that your main loop and re-entry code is now sitting behind some async scheduler, and - as you mention - will be more opaque and potentially harder to debug.