I agree that it would seem more consistent for the hermit to be considered a coinmaster, but making only this change doesn't exactly make things more consistent. You'd need some associated coinmasters.txt data, you'd need to treat hermitage purchases as coinmaster requests, and because there's 3 valid tokens, you'd need special handling for that too.
Even after all that, it also becomes an issue of how many people are already accustomed to the hermitage being considered a normal NPC and might be upset by the change.