Verified answer

A group of people generally interested in the same game bring their computers to one place (or sometimes go to a netcafe where they have many computers set up). They log on to the same network and play.

The main benefit is minimal/zero lag because you are all in the same room (playing across networks can produce a delay that diminishes the game experience).

It's also fun to be in the same room as you can talk to each other without needing a mic.

Usually you would bring your own monitor too, again depending on where it is being held.

The really elaborate computers just come with the territory. People who like to LAN usually have elaborate computers that are powerful enough to play the games they like, and there are also bragging rights associated with the best set up.

encyclopediadramatica.com/LAN_Party