It depends on what you're doing. When I am supporting seminars on Webex, I still leave email and other things running on the second display so I can continue t

It depends on what you're doing. When I am supporting seminars on Webex, I still leave email and other things running on the second display so I can continue to monitor the conference while keeping up with the piles of emails and tickets coming in. When I'm editing video or photos I can keep the document open and filling the main screen with tools right next door on the second display. Lots of reasons I like a second screen, mainly so I can see both desktops at once (rather than flipping between them). Its usefulness just depends on your workflow.