It's not about what they can or can't do it's attraction to the person. Also even then it's not just about the sex in a relationship, unless you're very shallow. Obviously a strap is not the same thing as a real penis. Also you can't give a woman a blowjob, only a suck her clit and stuff. Also the woman doesn't have substantial parts that you can rub off like with a man.Furthermore when I do become sexually active I will neither be the "man" (the one who penetrates), or the one who receives. I would be willing to do either role and ideally like to take turns.

I am a virgin but I would imagine that two guys in the same bed, like two girls, is better than heterosexual relations because in same-sex intercourse you understand how your partner's gear works.

But I also understand it's more than just the pleasure it's also attraction towards that gender

Its about attraction towards an individual. Sometimes they are male sometimes they are female.

What can a female not do that a guy can?

Do you seriously choose partners based solely on what they can do sexually for you?? "I cant believe you left your girlfriend for her... They both have a vagina you can stick it kn!!! What can the new one do that the old one cant??" maybe its a rich kid thing that i dont understand.