The specialisations are still in an early stage of implementation - I don’t know of any use for them apart from A: becoming a Patron, B: raising one’s stats above 200, and C: the two Persuasive uses that you mention. If you don’t have a clear and immediate use for specialising just yet, you might even want to hold off until more uses for them, and/or the ability to change specialisations, is implemented. (Personally, I chose mine on characterisation grounds, figuring that however they’re developed in the future, I’ll have fun along the way!)
Edited to make several corrects because apparently I can’t English.
edited by Sir Frederick Tanah-Chook on 3/1/2014