Yes it requires access to the pc but it's still a huge vulnerability. Many things can gain access to your pc but lack the permissions to do any damage. In this case simply having genshin impact installed put you at significantly more risk.
To your 2nd edit yes it is to do with it being installed. The user or the attack installing the anticheat is still the anticheat being used to exploit.
Yes it requires access to the pc but it's still a huge vulnerability. Many things can gain access to your pc but lack the permissions to do any damage. In this case simply having genshin impact installed put you at significantly more risk.
To your 2nd edit yes it is to do with it being installed. The user or the attack installing the anticheat is still the anticheat being used to exploit.