While it is important to keep WordPress updated to the current version there may be times when you want to control when the updates occur.
For example, if you do site maintenance for clients, you may want to do the updates on your own schedule after making a full back-up and not run the risk of the client clicking the update button before you are ready. You may also want to do some research about plugin compatibility before upgrading. Some people see the update button and are compelled to click the button – they just can’t resist.