Considering that snakes are wild animals at heart, I'm just happy when they're comfortable with me, without assuming or labeling it "affection".
It's no fun (IMO) to keep (confine) an animal, only to have it live in fear of you, because fear = stress for them, & stress affects their immune system & ultimately their health. So whenever possible, handling a snake so that it learns to relax with us is a win-win...it's relaxing & "in the moment" time for us, but it also helps our snakes to feel safe- to trust us to handle them. Considering that in nature, it's only a predator that picks them up, it's not always an easy thing for snakes to learn, but when they do, they may eat & function better long-term.