We are living in an age where the small laptop has become the best primary machine for most people. The benefits that current small laptops bring are:
Power. We live in a time where using a small laptop does not force you to sacrifice power. The processor and memory in a small laptop allow productive access to all of our favorite apps, including Photoshop.
Display. These days it's often the case that a small laptop will have a better screen than a desktop. For both high resolution and color accuracy more small laptops have great screens than ever before.
Mobility. It's no longer a big deal to go to Starbucks or on vacation with your laptop. We can bring the comforts of home with us.
Size. Of course size is a huge benefit. A small laptop doesn't command space like the laptops of yesteryear. Just set it wherever, it will fit. Pack it in whatever bag, it will fit. It doesn't weight that much either.
There is one drawback to all these benefits. Sometimes, especially if you're doing serious work you need a large screen. So for home or work use it's best to attach a big ol' 27-inch screen to your laptop and a bluetooth keyboard and trackpad. With this approach you have the best of both worlds.