Still probably not the right call, but if BYU can match or exceed what he'd make as a late lottery pick? And there's a decent chance he improves his draft stock and gets a better rookie contract out of it. It also reduces his risk of flaming out of the NBA, raises his floor a bit.
Downside is that it also lowers his earnings potential as it delays his second contract by a year. And there's an argument that he'd get even better development at the NBA level, even if there's some growing pains. Tough to say, lots to consider.