Hey there, T! That's a big, complicated question. And each person may respond to it differently. For many people, sex is biologically important. It's a stress reducer and the hormones released can do great things in the body. Many people also see sex as an important factor in an intimate partner relationship, as physical touch and intimacy does foster compassion and connection. There are lots of other people that are redefining sex and pleasure on their own terms. A good example of this are women with vaginismus, a disorder that prevents or greatly restricts physical penetration. And then there are lots of people that are asexual, which means they don't get romantically or sexually attracted to other people. And I think it's also important to call out that masturbation is also sex, and can be an important part of understanding your body and it's relationship to pleasure and release.
It's important for each of us to understand our own definitions of sex, how important it is to us, and what intimacy means (both with ourselves and with others). You get to answer these questions for yourself - on your own terms. And you deserve to be respected and supported, no matter what. Someone else's beliefs around sex do not have to be your own. You get to make these decisions. Your body. Your choice. Your pleasure.