Celebs using GOS has a different effect on everyone here, but I understand the appeal. I can only name Edward Snowden, The Hated One, Side of Burritos and Simon Walsh (Closed Network Podcast) who are all heroes in my book. I think I remember Nathan from NewOil also mentioning he uses GOS.
Most of them are not really celebrities in the common understanding. Most celebrities use iPhones and believe or trust Apple's privacy marketing, or they don't care.