Tutorial mentioned that headshots dont cause any additional damage. So why bother aiming at all? Why not just auto aim?

It was a technical limitation of older games that they had to check one less collission + controler aiming was not precise enough. I dont think it is a good idea to translate this 1:1 "just because that is how it used to be." Retro games should try to evoke nostalgia without implementing the (no fun) technical limitations of the past as "feature". I dont enjoy that ... but you do you.