As a woman who has asked a number of guys out... Confessions are awkward. Asking people out is less awkward. (Though it can have bad effects on a friendship sometimes too. IME closer friends are less likely to have their friendship destroyed by it though.)
Also, it's just kind of a pet peeve of mine when people give advice about "women" when what they're saying is really "for best results, treat this woman as a person." A lot of things aren't that specific, you know? There are some generalizations you can make about people of different genders, but IMO a lot of the best dating advice is of the form "treat this person how you would want to be treated, were you in that situation."
And I'm pretty sure having someone confess their love to you, when you don't feel the same way, is just uncomfortable regardless of your gender. Whereas having them ask you out is a little bit easier to move past because it's a smaller escalation of the relationship.