When you buy a domain that you plan to flip, do you also buy protection or any other extras? Do you pay for privacy? It seems to me that adding privacy would make it more difficult for buyers to find you.
Also agreed, privacy is defeating the purpose if you want buyers to find you. The only "protection" I use is the domain lock and very secure password and if you don't mind the hassle, use two-step verification.
All I know about domain protection is that it is essential for individuals that probably want to remain safe. I would look at this from the point of view that domain privacy protection replaces your contact info with that of the company that is providing the service.