To ask a girl out is not so easy. Girls are used to being approached by guys. So if you want to ask her out, you need to be different from others. May be you are not the guy of her dreams but what is the harm in trying. Girls often give chance to guys to impress them.
The new generation does not believe in old customs and so the very old pattern of a guy asking a girl out has changed and it does not matter who proposes. Guy especially like girls asking them out but females are sensitive and they do not want to get rejected.