I think Alec is as more natural 6th man then due to their skill sets. Burks strength is being able to come into a game and give offense right a way. He goes out and takes, where as Hayward needs to let the offense come to him and get in a rythem, and is a good playmaker for the starting lineup to insure that the team gets off to a good start.
Starters come out Burks comes in to insure the offense doesn't miss a beat. This isn't me bagging on Burks, just that he's a more natural fit to be in that role as a 6th man. For the record I can see Alec making an Allstar also feel that Hayward is a better fit as a playmaker-3rd option in the starting unit then he is leading the bench with lesser skilled players.