What's sex rated?
But no, it's not underrated. Sex can be a powerful tool in a relationship. Sex can build self-confidence. Sex can create extraordinarily strong bonds between people.
The plus side is that unlike other recreational activities, sex is completely healthy. It's fun. It feels as good as just about anything else you can do.
People who pass on safe, consensual, desired healthy sex are making an enormous mistake, imho. There's nothing virtuous about not having sex for the sake of not having sex in that context. Nothing. NOTHING!
I won't beat someone over the head about it if it's part of their religious beliefs, but I strongly disagree with idea that sex is bad in and of itself unless you're trying to procreate.