If you have the cables and hardware to connect your Wii U to your HD monitor on your computer desk, you need to try it. Especially for games like Pikmin 3 that displays different things on the TV/monitor and GamePad.
Why? If your monitor is on the same desk as your GamePad, you can place the two next to each other. Additionally you can easily reach the GamePad if you are only using it as supplementary controller. For example, Pikmin 3 lets you use the GamePad's touch screen to move a Pikmin captain you aren’t controlling. Otherwise, you can only control one captain at a time. The GamePad also displays the level's map screen which is not only detailed but changing dynamically to every action on the monitor screen in real time. If you can place your GamePad next to your monitor, you can easily look at these two screens at the same time.
Unfortunately this set-up isn’t for everyone (small desk or the lack of cables and an external sound system with speaker) but if you can, you’ve got to try it. The proximity of the PC monitor and you GamePad screen dramatically improves game play experience.
Here's a visual aid example from Mario Kart 8:
By having both screen on the same desk 1-2 feet(s) away from you, you'll notice and enjoy a better experience.
Edit: The GamePad actually has a head-phone jack as well, so a sound system isn't even necessary for some of these games like Pikmin 3.
