Logically if a man is bisexual he's allowing interest from both sides of the aisle, theoretically increasing his pool of potential intimate partners by 50%. So in that sense ... obviously yes.

The more cogent question would be: who regards a man as "more attractive" in this context, and in what way is he more attractive?

I suppose it would depend upon what attracts the people he encounters. Bisexuality would not make someone more attractive, or less so, for me.

Why would it?

I've heard he's twice as likely to have a date , come the weekend .