Some games have better tools than aim trainers
Aim trainers can be extremely convenient in games that don’t have the necessary tools to practice every aspect of your aim. For example in CS:GO it is not as common for pro players to use aim trainers unless they are sponsored.
Nearly no pro player in CS:GO consistently uses an aim trainer without being sponsored. This is because CS:GO and the steam workshop provide a wide variety of training maps that players can use to train every single aspect of their aim from flicking to target switching and tracking.
The best way to practice your aim for a specific game is by shooting the targets in that specific game. This is because the movement, target model and all the mechanics are the exact same when you’re training in the same game. However, if you switch to an aim trainer, the resolution, sensitivity, movement, target model and field of view can all be completely different, which is why a lot of people don’t see a direct translation in their aim from aim trainers to games.
However, in games like Fortnite, there are a limited amount of tools that you can use to train your aim which is why it is very popular for pro players to use aim trainers. When Kovaak 2.0 first came out it was widely used by a lot of the Fortnite community because players wanted to get an edge over each other.
Valorant is another game which aim trainers are very popular among professional players. A lot of these professional players only use Aimlab for example to train their aim and nothing else within the game.
This could have been because there was no deathmatch mode in Valorant for a while or because Valorant’s bot target range is not as good as some players would like. The target range in Valorant only consists of a few floating targets and a single training area with limited options.
A lot of pros that come from CS:GO and moved to Valorant are used to maps like “Aim Botz” which provide a wide range of options to let users practice every aspect of their aim. Perhaps this is why they are dissatisfied with Valorant’s target range and have moved on to programs like Aimlab.