The reason for this is very simple. As ADC, you have the car to attack rivals from a distance and stay alive. Typically, winning a team fight involves eliminating the rival team's shooter. This is because the ADC is the only role that doesn't need its skills to deal a lot of damage to rivals. Moreover, he does it from a distance, so with the support of his team, one ADC can clear the entire opposing team off the map.

However, there are also downsides to being a shooter. Your strength depends on the items in your inventory, because you need them for your auto attacks to deal more damage. What's more, your skills usually rely on moving or amplifying attacks. So against an assassin on the first levels, you don't have a chance to survive, because his skills are much more useful than yours, and your auto attacks are more or less at a similar level.

Therefore, in bot lane, a support plays with the shooter. His job is to help the ADC survive this more difficult period of the game, until he has finished at least one item, when the shooter begins to play a significant role in the team. This is how all older characters are played. Jinx, Ashe and Sivir work exactly the same way.

Over time, however, Riot Games began to introduce some variety to shooters. Most of them involve giving them a skill that allows them to move quickly. For example, Caitlyn and Tristana both have "leap" skills in their roster. Despite this, they are still used as traditional shooters.

By contrast, Lucian, Vayne and Quinn are also often found in the top lane or even in the mid. These are shooters who are able to take care of themselves, and if they do not have to share their experience and gold with the supporters on the line, they are able to dominate the opponent and take control of the game. However, they occupy their strength with a short range of auto attacks. Therefore, playing them is very demanding, because to deal damage to your opponent, you almost always come within his range.

Apart from that, there is one more type of ADC who do not fully fulfill the basic assumptions of this group of characters. It's about heroes like Varus and Corki, who have always had a lot of damage in their skills. This means that they do not necessarily want to auto attack their rivals. They feel good standing quite far away and hitting them from a distance. So depending on the version of League of Legends, we saw (and did see) a lot of Varus and Corki in mid.

There are also some very special ADCs who like to play assassins. Kai'Sa comes to mind first, and with the help of an ultimate skill, she eagerly jumps into the middle of a team fight to eliminate one target. On the other hand, isolated targets are loved by Twitch, which can become invisible and catch someone while rotating on the map.

However, each of these characters essentially relies on careful positioning and constant attacking the opponent, remaining out of reach, because although they are extremely strong, they are very easy to eliminate. Being an ADC requires a lot of responsibility from the player, because in the later stages of the game his every mistake can mean a defeat.