At the top of a draft you draft for realistic upside. That's because a superstar is worth 10x as much as a solid starter in this league. By realistic upside I mean top 30th percentile outcome.
Embiid has by far the best 30th percentile outcome in this draft. Even if he also has a 30% chance of busting, well, I'd rather take that chance than to pick a future role player with only theoretical upside, like Wiggins.