Playing college ball offers better money, more hype, more visibility and more brand awareness. Demin and Hugo illustrate this perfectly. Just a couple months ago, most mocks had Demin and Hugo towards the back of the lottery, but usually Hugo a few spots ahead. After less than 5 games in college, Demin is getting a ridiculous amount of publicity and he's suddenly jumping into the top 5.
I'm convinced Hugo would be getting similar treatment if he was stateside, same way that I think Luka would have gone #1 if he'd played college ball. And now that top euros don't have to give up money to play over here (in fact, they'll probably make a lot more), I think we're going to see an absolute deluge of euro talent in college in the next few years.