One of the main reasons for choosing a desktop computer over a laptop or tablet is that you can get more performance for your money. Or, if you prefer, the same performance at a lower cost.
If you want to play the latest games or work with processor-intensive applications and store large amounts of files than a desktop PC is a great choice. The other big advantage with most desktop computers is that they are easy to upgrade, extend and improve the performance of. The requirements for computers becomes constant higher and higher, and a computer that is two or three years old can already start to feel inadequate. With a desktop PC it's relatively easy to insert more memory, faster hard drive, replace the processor or add a new graphics card.