He is a guy who can score points for you with out having to run any offensive sets for him. That is a valuable player. He can score in transition or on put backs in the 1/2 court set.
I think people worry way too much about positions. You can be a 3 who scores all your points from posting up if your coach runs offense through you. I just think there is not a need to run offense through White at this time so Iowa is not going to set him up to score more. He is a bad 3point shooter so when he hovers around behind the arc he will not get points consistently there. When he is feeling like his shot is falling he seems a bit more ready to shoot those 10-15 foot jumpers. When his shot if off you tend to see him put his head down and find contact. He is good at finding contact and getting to the line.
I mean you could pull Basabe out of the lane and let White work on the block with he and Woody but why would Basabe's guy follow Basabe out around the perimeter when Mel is no threat to score there. White can rack up points when the matchup's favor him and can be pretty easy to shut down when the match up does not favor him.
In terms of 3 vs 4 those numbers are pretty meaniningless. It's not like if you play the 4 you are now allowed to post up whereas if you play the 3 you are forced to be a perimeter player.
Basketball is far beyond the 1,2,3,4,5 positions as many old timers like to refer to positions. It is about match ups and putting your best players on the floor.