If I was an online ghost I would never get hired. In my line of work you need a CV with publications. While you become a public figure in the process of publishing papers, its actually proof of work vs. trying to talk about your proprietary little thing you worked on at company X that you aren't really allowed to go into specifics about, or doing an interview exam on one tangential problem you may or may not ever encounter in the job like you are in undergrad again. If the recruiter wants to see what I can do, they can just read what I wrote, and ask me for clarification rather than total explanation.
Another massive benefit of being a public face is that collaboration is now possible. Two people in the same Uber pool ride in SV could be struggling with the exact same issue and have no idea that the other person exists because the CS field is closed off and proprietary for the sake of shareholder profit. Think of all the investment and engineering by a half a dozen companies towards the same exact goal of a self driving car. Imagine if all those NDAs were ripped up, and every engineer met up at a conference, gave talks, held poster sessions, troubleshooted common problems, set up meetings, emails, collaborations, joint efforts, shared resources and data, etc.
But then, of course, no company will be able to 'win' and dominate market share and print money for the shareholders.