Today ASAP notifications will be sent within 30 minutes. It can be even greater due to variability in the notification queues. If there is a large number of notifications going out at once, this could cause the time it takes to send to be greater.
30 minutes can be a very long time span, if you think of usecases like
1) asking for an app review after a event completion, or
2) a welcome message after a verified sign-up.
It would be better to have kind of a "hardcoded behavior" which executes and shows a (cached?) display notification immediatly after the targeted event trigger. Th emain difference probably would be to use more event-focussed triggers instead of people-focussed triggers .