Say what you will about the style of the 2-door sedan, there are two things that cannot be denied: They're a stronger unit in a side-collision (T-boned), and the windows sealed out the wind noise and rain much better than the hardtops did, especially once they had a few years on 'em. Anyone who has ever owned one of each will know exactly what I'm talking about.
Also more robust in a rollover situation. A more rigid body shell all around. While I do like the 2 door hardtop "pillarless" look (as my '67 Chevelle had), I wouldn't turn down a '55 or '57 2 door sedan, I don't think they look too shabby, but I do get where everyone is coming from.