That’s not their point. Their point is they have to get your useless notifications at 3 am and check them even when they aren’t urgent because you can’t know which is which until you read it. Stop texting people at 3 am unless it is urgent.
If PagerDuty goes "ding" at 3am, it's probably best to take a look.
If Slack goes "ding" at 3am, maybe you forgot to turn off notifications or something, but by no means do you need to even read the notification.