From what I know, it's not different from a normal person. The vast majority of people with aphantasia just live their lives normally. I've been trying to open my "mind's eye", and it's made me realize why I have trouble understanding certain concepts and reading certain books. I'm pretty good at math, but English has typically been my worst subject.
Hmmm, well I don't think JRPGs are necessarily the same thing as visual novels. Visual novels are games where the players takes a role, (for the most part) but I wouldn't categorize Final Fantasy as a visual novel. On the other hand, I would consider Ace Attorney and Dangan Ronpa to be visual novels, even though they do have some gameplay aspect to them.