I have designated my preference for earning points rather than miles. However, I see promotions for miles (users) much more frequently than if you collect points. i.e., earn triple miles when staying three nights, earn a free night by your third stay, etc.) Can someone clarify why one preference would be better than the other. Thanks.
It's really a matter of what you will get better usage of ...points or miles. If you need to get some airline miles for a trip, one can change their preference to miles for the airline of their choice. It is far better than earning points and then transferring them to airline miles which is very costly to do since the value of the points is greatly diminished when points are transferred that way. If you need hotel points, then that is the way to go.
If one wants to take advantage of a particular promotion they can change their earning preference to get the deal and then change back if they like. I don't believe there is any limit to the number of times one can change their earning preference from one to the other.
Hope this helps.