Man is an over-complicated organism. If he is doomed to extinction he will die out for want of simplicity.
Designers of interfaces often present users with a choice of methods. For example, both a menu item and a keyboard shortcut may execute the same command. In most word processors, you can move a contiguous portion of the text by either (1) the three steps of selecting, cutting, and pasting or (2) the two steps of selecting and dragging. Also, the selection process itself can be invoked in more than one way. The user has a smorgasbord of methods.
One justification for having multiple methods to do a given task is that some users prefer one method and other users prefer a different method. For example, a novice user ...