Either way it's completely anecdotal. I would venture to say there's no correlation between how someone looks and how someone performs.
The KEY information here is that they're at the same rank. That means the slob has had to overcome people using the heuristic you've just described in order to reach the same rank, probably through being an objectively better surgeon.
I would argue that if someone looks the part, then they can be successful with a lower level of skill, and so they have less incentive to really be as good. My impression is that people generally, and doctors in particular, are quite lazy and generally aim to only be as good at a thing as they need to to get what they want, so the guy who looks the part is likely to be less competent.
There will be exceptions obviously, but I know that if I meet someone who puts a lot of effort into appearances, my presumption is not that he does this because he is incredibly hard working and just puts more energy into everything. In my experience that's not usually the explanation.
I would guess that's the most common reason for people to look the part. I can't really tell if you're agreeing or disagreeing with what I said!
I could save time in the bathroom by not washing my hands, but I'd rather not.
14 years of schooling vs 30 min on the internet?
I'd say the effort trade off is statistically insignificant.