This provides consistency ie: it doesn’t matter whether the female remained single, married once, twice or more, was widowed or divorced, her maiden name always belongs to her. If females are recorded by their maiden name you and others will always know how to find them in your tree as they are all recorded the same way. Use of the maiden names also ties them to their birth family and that is an important step in finding her ancestors.
When searching you would search by maiden and married names. If you are using software, then as long as you have the female entered by her maiden name and add her spouse then most genealogy software programs automatically searches by both her maiden and married surnames when looking for records about her.