Maybe Mika's advice was - look, you're pretty athletic for a kid at BYU. But look at what the other guys who are 6'9"-6'10" are doing in the NBA. That's who you're up against. You don't have the athleticism or freaky size to really stick in the NBA. So declare for the draft - if someone decides to take a shot on you, great. Worst case scenario you go make six figures living in Europe for a few years - then come back, finish school if you want, and start a career.
I seriously doubt anyone was telling Mika he was going to be a lottery pick this year or next, or that he was a sure thing for the NBA.
I think he knew exactly what he was getting into, and got basically what he wanted.