Glad you enjoy the story. Though that’s the thing where the story and development with the characters come in as you will see more lewd stuff as you grow with them.
But they are more than just for sex as they are still characters with defined personalities that will have their limits on things they will do too.
In terms of amount each of the main girls has various amounts of scenes but I understand what you are saying. Everything has a purpose and is done for a reason based on the story