I do think, although Buttigieg has generally gotten favorable news coverage, the "boy genius" stuff is a pretty straw-mannish and inaccurate caricature of why (some, though certainly not all) D voters like him.
His positions on the issues are pretty well-calibrated relative to the D electorate. He's been good in debates. As the first major LGBTQ candidate, his candidacy is historic, He's young in a field of old folks. He can paint himself as an outsider. He's Midwestern (helps in IA).
To be clear, I'm marginally skeptical of the sustainability of this surge and whether it spreads beyond IA/NH. But there's a fair amount to work with there and he's an unconventional candidate.
