There’s a conflation of concepts here. Having an erection and enjoying sex are two separate things. Porn stars take Viagra to stay hard for uncomfortable sex for instance and men have been slipped Viagra to make it easier to sexually assault. It’s easy to give a man an erection. The mechanism is well known that you want to ultimately get vasodilation going on in the corpus cavernosum so blood pools there. Enjoying sex more is a much broader thing for women (and men). It’s possible that someone who had a pubic nerve injury or has cardiovascular problems would have better sex with Viagra. The problem might be elsewhere. Maybe it’s trauma. Maybe it’s pain/vaginismus. Maybe it’s not having explored one’s body yet.