Many people believe that click speed is not very important or not important at all, and on the grand scale of things, that might be true, but when it comes to gaming, things change drastically.
Any game that utilizes mouse clicks for attacking and defending can register a certain number of clicks per second or CPS and each time the player clicks, there is a certain delay of a few milliseconds until that click is registered within the game and while in most cases this can’t be noticed or timed by the player, it becomes very important and noticeable in the game itself.
Being able to do more CPS will allow you to attack more frequently, thus allowing you to perform combos when attacking and take down your opponent quicker and without taking so much damage in return providing that your opponent does less CPS.
This is extremely important in PvP scenarios in competitive games and having a higher CPS count will allow you a greater chance to win. It is important to note that other factors such as the latency of the server and your personal internet connection play a big role as well, but that is not the topic here.