I agree with you that it does draw a lot of attention to the personal, emotional relationships of Hardy, Ramanujan, Littlewood, and so on. But, for someone who has already read and loved "A Mathematician's Apology" and studied math in college, reading about these personalities can be quite fascinating. Of course, since this is a novel, it's hard to say what is surmise, what is fact, and what is invented. I never was able to find much biographical material on Hardy (I was only able to find 2 pictures of him (this was in the 80s before Google)).

I need to read the book on Ramanujan you mentioned, though.