Traditional tower PCs take up space for the tower and space for the monitor.

Laptop PCs are about 60% more expensive to buy and maintain than towers, and the keyboard is necessarily restricted.  Upgrading is often not even an option.

Introducing the LCD PC.  This has a footprint no larger than a normal TFT/LCD monitor, but by packing the system behind the monitor, you have space to upgrade and maintain the device at a price similar to that of a tower PC.  The depth is only about 6" so it can fit anywhere without looking intrusive.  And with a 19" screen (laptops commonly have 15") you have space to have several applications visible concurrently.