Well some of us have jobs that take us all over the world, and having a nice laptop that you can do just about everything you can do on your desktop that is anchored at home fits the bill. Not only can you get stuff done, but you can get some entertainment and have some comforts of home with you. Other folks like to go to meet up with friends for a LAN party. There are tons of reasons, but regardless he has a valid question.
I am not sure how to use both cards, or if it is possible, but you can force your NVIDIA software to use NVIDIA card over the integrated graphics. You can right click on the PD exe file and select "Run with graphics processor..." and then select the one you want. You can also go into the NVIDIA control panel, select 3d settings, and then select High Performance NVIDIA Processor under the preferred processor setting. You can also create a custom set of settings for power director under the programs tab.
In PD, make sure you go to preferences and check all the boxes under hardware acceleration. When you produce a video, only some types of codecs can use the hardware acceleration as well. If the selected CODEC can, you will see the box next to Fast Video Rendering Technology enabled.
I think there might be some misleading labels used for the hardware acceleration, but as long as it is enabled in the preferences and selected on the produce screen you should be good to go. Also, you need to make sure you have current video drivers loaded for the cards. There are some issues with the older NVIDIA cards running the old architecture. If you have one of the older cards described in written by Sonic, then you will need to do some tweaking to the drivers. Sonic is the subject matter expert on that and should be able to help you out, so check out his sticky thread.