The safety is on, till you are on/in your sights, a target/threat that you want to engage. With good fundamental safety practice, it will become second nature to disengage when needed, and re-engage when not. Any other practice of the use of the safety is irrelevant, accidents happen, and this is just another layer to keep everyone safe.
Pick a scenario, if you need your rifle to defend your/a life: bad guy next to your kids bed room, neighbor walking the dog, over the berm at the range, your partner behind/in-front of you (yes lots of ankles get shot by friendly’s)
Then add: moving, mud, fixing a malfunction, slipping, kids toys, darkness, adrenaline, dogs piss, maybe your own piss…
You let one slip and do the math.
By the time you can identify a threat, place sights on it, make sure it’s an actual threat, and ready to pull the trigger, the safety is a fraction of that time to disengage.