Davis ain't ready yet. In order to play in FIBA basketball he needs to put on some weight and being able to shoot and create his shot. He's already a great defender and good passer but he needs more.
If it were any other national team, I would agree with everything that you said. Your comment above is why Davis has a role on this team. I fully agree that he won't get the same opportunity to get to the rim against a legitimate competitor and that is fine. So long as he keeps making his runs the defense needs to take him seriously and if they lay off, he'll make them pay with an alley oop.
The moment, that the US is depending on Davis for offense is the moment that they are in real trouble. Don't get me wrong, I wouldn't want Davis to play 30 minutes against a team like Spain but I definitely think that he can give you a solid 7-10 minutes off the bench to help take some of the pressure off of Chandler.