One of the things about phone calls is that they will continue to ring and ring until you actively decide to answer or ignore; it's not just a half-second "ping!" sound delivered once. This is also useful in meetings when everything else is closed up or silenced, to jar you out.
I usually do not respond immediately to phone notifications, which I can handle async. Phone calls are by definition sync.
Ah yeah, these are no ordinary phone notifications. :)
Heii On-Call will keep alerting you with these “Critical Alerts” until you’ve manually acknowledged. (Or until it escalates to a teammate and they acknowledge…)
And at least on my phone they sound nothing like normal phone notifications, which I personally always have on vibrate and/or DND anyway.
I usually do not respond immediately to phone notifications, which I can handle async. Phone calls are by definition sync.