If you ask a guy out it gives him all the advantages. Yeah some guys like it because they may be too shy to initiate things with a girl, but if they really like a girl they shouldn't have any problem asking her out. They better ask her out before someone else does. But if you ask a guy out it sends the signal that you are REALLY into him and that can lead to him possibly taking advantage of that. Guys like girls that other people want so if you ask him out that can look like he's your only option.