Guys it's just porn it ain't that deep
There are 15 pages leading up to the smut, I think it's perfectly fair for people to discuss the content of the first 2/3rds of the book. And, like, for men who have a tendency to just jam it in at the first opportunity those pages probably don't matter, sure, but for most women setting a proper mood first is as an important part of making something appealing as the actual sex, I think. Not that I don't enjoy plain porn, but a good doujin can be so much better than that.
As a person that enjoys both works I feel like the creator, in my opinion, did a fine job setting the mood in both. The relationship between Chisato and Takina feels intimate to me, and the sex works well. Of course if people disagree with me that's fine as well, just for me at least there's a romantic and intimate mood in both that works well.