A laptop computer desk can be perfect if you are severely limited on space. These desks are very compact and in most cases only have enough space to fit the laptop itself and a few small items. If you are looking for something to use your desktop computer on and you do not have a lot of space for a desk, a corner desk might be better for yor needs. Additionally, if you are looking for work space for paperwork a larger desk would be better as well.
Standard desks that are used for computer usage usually have a separate shelf for the keyboard and mouse, but that is not the case with a laptop computer desk. These are generally only the table top with no frills, but that does not mean there are no variations to the standard. There are plenty of different kinds that can provide you with comfort and ease of use.
There are models on the market with an attached shelf on the side for convenience, and some variations have an upper shelf to place the laptop if you have a separate USB keyboard and mouse. They sound very simplistic, and that is essentially what they are. They are very efficient, compact, and easy to move desks -- very much like the laptop computer itself.
Many manufacturers make standard styles and portable styles. Standard is what you would expect from a desk construction-wise: solid wooden or steel frame, possibly with a glass top depending on what you like. Portable models are foldable to take with you from place to place with ease. The portable units are great if you travel often or if you are going somewhere and are not sure if you are going to be able to find a place to use the computer.
There are also types that are literally laptop computer desks: they go right over your lap. If you like to lounge at home while on the computer and do not want to be tethered to your large desk at all times these are very convenient and are often fairly affordable. Another bonus to these is that many of them also have built-in fans to keep your computer cool, which can be a big problem depending on your laptop model and age.
It should go without saying that any type of laptop-usage desk is going to be cheaper than larger desks. The fairly simple construction makes for less materials, and hence less cost. They may not be useful for desktop computer users, but for those with laptops they are very convenient and extremely affordable alternative. Laptops are all about convenience, and the laptop computer desk follow that trend and do it well.