SEO should be a bridge between technical and non-technical people that build out sites.

No site's output is 100% because of the tech team - content writers can put in weird code, marketers can add all sorts of stuff to say Tag manager, the robots.txt is likely from 2008. And a site built with code as the primary goal is likely lacking in some marketing oomph somewhere.

Someone who's job it is to find the right balance, and aim to maximise the returns from the single largest source of traffic, is pretty valuable.