Is sex really a bad base for a relationship?

I've ran into a lot of females who think that sex would be a horrible base to build a relationship around. I disagree. Some might say you should base a relationship on trust and or communication. I can see where they are coming from but in my opinion why does it matter as long as its a strong base? You can talk to someone for months without sex (communication) but then have sex and can no longer be interested in them. You can trust someone all you want but not be physically attracted to them.

I know a few women who have guys they can go to and trust and also have great conversations time and time but would never date them. That natural feeling you get called being horny is undeniable so why you can't you build a relationship off of something you feel naturally? What's so wrong with that? Nothing is wrong with that, that question is rhetorical.

Now in no way am I saying that you should just purposely go out and sleep with someone then try to build something around it. I'm simply saying don't be appalled at a relationship forming around being sexually attracted to someone. You have to start somewhere right? In my head I think people think too hard about it, just let it be. If you make a base just make sure the base is strong enough to withstand anything so if you gone base it around sex you better be porn star status when them lights go off. If you want to build a relationship on trust and communication that's great too, just don't object a relationship because you were sexually attracted to the person from jump.