One of the biggest issues for the Phoenix Suns this past season was size. The team was often seen playing a small forward at power forward or the likes of Dragan Bender or Ray Spalding. They possibly could have put Richaun Holmes next to Deandre Ayton in the frontcourt but then they really wouldn’t have a center off the bench.
You don’t draft just because of size, at least not in the first round. However, the second round of any draft is a complete shot in the dark. The vast majority of second round picks end up not making it in the league.