Some may be proud of a title, but many are on LinkedIn because they may need to get a real job in the future. An assignment is not future-proof anymore.
Where I live, in the Netherlands, a religious activity on your CV is not a recommendation. That is why many try to diffuse what their background is by using WTBTS, instead of the name Jehovah's Witnesses. The problem is that you have to explain a gap in your CV. Even Ex-JW's have this problem when they have been in Special Fulltime service.