A laptop is useful for lots of things, but when I really want to get some work done, I need screen real estate and a full keyboard and mouse.
My main compute is a laptop with a docking station. It has external keyboard, mouse, dual monitors (can connect via hdmi, displayport, vga, or dvi), audio, networking, etc.
The only downside to my laptop is that it maxes out at 16GB of RAM and the CPU is more limited than what you could put in a power-hungry desktop. But the peripherals are all supported.