The person that wrote this article has very strong opinions, but a pretty valid point. Providing no information and nearly no contrast, a disabled button is the quickest path to form fatigue. The buttons that have been disabled usually contain a call to action, which makes it especially infuriating when they cannot be pressed. This frustration is made even worse when the disabled buttons won’t tell you *why* they are disabled. Then the user has to begin a scavenger hunt to figure out what they have to do to make that button work.
“It is a bad practice to disable buttons. Disabling the button prevents our chance to tell the user what is wrong. The user keeps clicking the button and is totally in the dark why nothing happens. Keep the button enabled. Let the user click the button. Then show the message why it can’t proceed.”