I don't think they're that mutually exclusive. "SEO" is mostly just a matter of figuring out some basic things, and if you're actually being professional about it, doing some testing.

After all, that's why he's able to automate it.

I'm much more impressed with people that do two things that are relatively further apart, such as someone who can hack kernel code and also has good design skills.

That's not to take anything away from what he's done, mind you - any startup is something to be proud of. I just don't think it's miraculous that a good developer is also able to get a good grasp on "SEO".