I think our MC has the right idea and it isn't compensated dating, especially after she got back plopped herself down on the couch and called grown-ups idiots, but I could be wrong. It just doesn't seem completely like a compensated dating situation.
I also think that Hebikawa does want to be friends with Kusunoki, but so far as we have seen can't get over the frustration she feels when with Kusunoki. Kusunoki really is a mystery to her and she can't believe someone wouldn't be putting up a front like she does around everyone. Honestly, I do wonder if a lot of her personality including the negative part is legit just a front so she doesn't get hurt due to some sort of potential family circumstance?