More Kase and Yamada is always welcome, but I'm grateful for this chapter in particular because Kase's expression at Yamada's kiss addresses (in its way) the one thing that has always bothered me just a little bit about the series--in every previous example of kissing/serious romantic skinship that I can think of prior to this, Yamada's expression has been like a deer caught in the headlights, at least initially.
It's not that she's unwilling at all or doesn't welcome the contact, but when we can see Yamada's face the visuals have always looked a little like kissing is something being done to Yamada rather than something they're both participating in and enjoying equally.
Granted, being in a clinch with the goddess Kase could make anyone think "OMFG, can this really be happening to me?" But by now (and by then in the story) Yamada knows that she's absolutely adored in return, so it's nice see her muster a little plant-appointee savoir faire of her own, if only for a microsecond.