Personally, I couldn’t even enjoy sex if there wasn’t some minimal emotional connection. If there isn’t some human element of connection it’s as @majorrich says “mutual masturbation”.
That said, is there anything wrong with “mutual masturbation” ? That depends on your idea of what sex is and what gives it meaning.
What is meaningless? It depends on the person.
For one person physical sensation has enough meaning to keep the sex from being meaningless. For another “mutual masturbation isn’t enough to give meaning.
I have nothing against “recreational” sex as long as it’s honest, that is, both people understand that it’s “recreational”. If one doesn’t, it means the other person is taking advantage of them and their emotional vulnerability.
It’s a gift to give yourself to another human being in the sexual act. Oh sure we joke, and some of us want to trivialize it, reduce it to an animal urge, a biological impulse. But I don’t buy that. We are connected emotionally, physically and mentally. Each of us is one human person not 3 separate and distinct entities. When you have sex/make love to another person what you are sharing is intensely personal. If you choose to see it as purely physical you are in denial of your own essence as a human being, your integrity, i.e. “wholeness”.