Some of the books I've written have sex scenes in them. Some don't. In the ones labeled as Christian romances, which are all my Awe-Struck books, there are kisses and hugs but nothing further. There's also an element of faith. My Prism Book Group sweet romance, Daddy Wanted, and historical, Patriot's Heart, also have kisses and hugs, but nothing further.
My paranormals all have sex scenes. The reader goes into the bedroom right along with the protagonists. In real life and in fiction, sex is powerful. It can really mess things up emotionally for the characters. It ratchets up the tension since the characters have more to lose.
However, all my books are romances, which means readers are guaranteed a happy every after ending. But readers do have a choice as to how much heat they prefer in a romance. If you're not sure about a book, check https://www.allromanceebooks.com. They have a heat level indicator for every book, represented by flames. :-)
For a quick guide to the heat levels in romance, check out https://www.goodreads.com/author_blog_posts/4776761-romance-heat-level-ratings-sweet-spicy-and-hot