Could have sweared i read this one already but i can't find it strangely enough. But yeah, old hentai hit differently, it's like... They would actually cared about the story and their world. There is even a small hint of a story like "will the heroine realize that the best sex she had is with her little companion". It's not much, but it gives some sort of relationship you could be curious about for the next chapter.
Of course, nowadays there is ecchi for this kind of things which often goes less far that kind of book... And the hentai evolved to be way more "functional" which... I suppose is not bad in a way ? But i kinda like reading a big adventure with sexy developments and actual stakes from an author that actually try to create a story from time to time.