The fundamental problem is there are two kind of sleep function. One that actually sleeps and other that is a actually a timer that just calls certain callback

The fundamental problem is there are two kind of sleep function. One that actually sleeps and other that is a actually a timer that just calls certain callback after a desired interval. Promise is just a syntactic sugar on top of second type. Go certainly could call another function after desired interval using `Timer`. I think better comparison would be wasting CPU for 10 seconds instead of sleep.