I think the main benefit is in personal satisfaction. If you mean in a professional environment, then I would doubt it very much. As photography is a freelance business, work is going to go to those who can get the shots - not those who have got the qualifications, per se.
The RPS is a recognised society with a certain amount of gravitas. Personally, I am working towards an LRPS distinction, because it marks a sense of photographic achievement for me.