I agree with you on the point that there's more to compatibility than just sex. Goals in life, personality traits, even sense of humor etc. have to be reconcilable for it to work long-term.

On the other hand in my opinion a sound and satisfying sex life is the foundation for all of this to work. For many people sex plays a pivotal role in strengthening and reaffirming their bond with their partner. And there's just no guarantee that two people click in bed solely based on mutual chemistry, which is an argument that can be made against staying a virgin until marriage, because this way you can't explore your sexuality and that may lead to a whole lot of unpleasant surprises and annoyances when you finally start exploring with your brand new spouse. Liking or loving someone doesn't automatically translate to compatibility in bed which is why I think people shouldn't bother guarding their virginity. But that's definitely up to personal preference and if someone feels that is the way they want to live their lifes more power to them.