No. If there’s nothing there physically for you then you should politely decline offers to date. It’s tempting to think that such a relationship would be good enough even without that spark. And it can even work for awhile.
But it’s not fair to the guy. Girls often just do not realize just how much a guy’s self-esteem is wrapped around his sexuality. And if it’s not there for you at the beginning, if there’s no way you could find yourself attracted physically, then there’s no way you ever will. And being with a girl that’s not attracted to him eats a guy up. The breakup will be bad.
Some guys won’t really care whether you are attracted to them or not, so long as you’re willing to sleep with them anyway, they’re good. This is even worse and you should run screaming from a guy who is like this.
If you think he’ll make a good friend, then just be his friend. Make it clear he’s not getting any, and don’t lead him on. Sex is something you can only really get in the context of dating and relationships. Stripping sex from both robs you of true happiness.