The main reason for using templates is efficiency. While creating a template, you go through common tasks only once when you need to deploy multiple VMs that are the same. For all future VMs, you don't need to go through the same tasks every time you need a new virtual server.

Another reason for using templates is that they allow the elimination of human errors. Often there is a need to have two or more identical servers in a production environment. Going through the same setup tasks for each server is not only labor intensive, but also highly error prone. A better way would be to create a template once and deploy each new VM from it. Have a look at the following figure:

The more VMs you deploy using templates, the more time and effort you save.