I like animations as much as the next guy, but not every game can be City of Broken Dreamers. However, there are plenty of games, in my opinion, that have very good and hot sex scenes with just a handful of renders. Sure it is not smooth like a fully animated scene, but it gets the point across and can be hot to watch if done well.
The problem with the two sex scenes in this game, is that there is no passion, no real sense of excitement by either character, especially the MC. It seems more dutiful than anything, like the MC says "Well, I guess I better do it then."
Kayla and Lucy, in their scenes, say they are into it, but I was just not feeling it. It was all very dry.
I really didn't get the sense, especially with the Kaylah scene, but also with Lucy, that the MC was enthusiastic, and the whole scene was just cold and lifeless.
I know that these are mainly side characters (sorry Lucy lovers), and the dev is saving the big effort (hopefully), for the more popular LIs, but the scenes were very, very, disappointing as a player. It would have been better to just skip it, than to give it such short shift. It seems like the dev isn't really into the sex scenes himself, and just threw them in to please the fans.