While a trigger, loose or tight, effects the ignition of the cartridge, a loose trigger may affect practical accuracy by causing an inconsistent feel. In practical terms, no slop is better than slop.
While you are certainly correct about effect vs affect, you are wrong on triggers. The trigger pushes the sear off the hammer, it has absolutely zero impact on ignition of the cartridge. The moment the hammer starts moving forward to trigger has completed it's job and well before ignition starts. Also a sloppy trigger is only sloppy when there is no pressure against it. When you press a finger up against it, no slop. Since we use a finger to shoot it, that becomes a moot point.