That ability is different in every game, because every game is different. Even between different Halo games, it is different. Of the people I have grown up playing Halo games with, some of them are better at aiming in the older games and some at newer, cause they are different.
Aside form that, landing shots and getting kills is probably the most mundane part of the game. That’s why games like CoD are so incredibly boring. It’s just pull trigger, they’re dead. That’s incredibly boring when you do it hundreds or thousands of times.
What’s fun is footwork, strategy, juking out and using the terrain to your advantage in ways the other player(s) didn’t expect. You can’t do that if landing shots is easy and disorienting your target to make them miss is ineffective. In the few days this game has been out I’ve clambered up and around to juke out an enemy or grappled around them to make them miss as I fly behind them multiple times; that’s a blast, but it wouldn’t work if they magnetically hit me even when I do something to evade their shots.
And, as someone who plays both M&K and controller, I find there is little difference. The controller has a bit stronger aim assist, but it isn’t really necessary to have that when aiming with a mouse as you can hit the target just as easily as long as you can predict their movements. And that’s the key, people move differently in Halo than other shooters, so no CSGO or any other shooter doesn’t translate; aiming is about knowing how people are going to move so it only translates if people move the same way, which is not the case between all different FPSs and certainly not Halo.