If you are doing most of your browsing with a mouse a button is more convenient.
To my shock she can have 20 windows open at one time.
Clutter is one of the most minor of sins. Otherwise, my apartment will condemn me to Perdition. On a serious note, some of us have the ability to multi-task. You can have multiple windows open at once. However, you cannot have multiple tabs open at once.Is there a reason why she wouldn't want to have the same 20 pages open in 20 tabs? Browsing the tabs back and forth is less a hassle than having 20 pages with one tab only in use open, and it looks less cluttered too.