I guess it's really just a matter of appropriateness. And context, and ratios. I write so little fluff, and they're both so much *healthier* in zombie!verse than in canon despite still having piles of issues, that a little fluff in that context felt appropriate, especially since it does still at least tie into one of his physiological issues. And even in BtB, there was the waffle scene which WAS fluff, just inserted midstream in an otherwise dark story so it wouldn't get noticed as such haha.

Whereas writing a story where he decides post-Roche to open a dog rehabilitation sanctuary and becomes FRIEND TO THE ANIMALS and rolls around in the sun with puppies all day, would not be appropriate.