It’s understandable to feel that way, but it tells the user that this decision doesn’t have to be permanent and makes it easier to say no if they aren’t sure. R

It’s understandable to feel that way, but it tells the user that this decision doesn’t have to be permanent and makes it easier to say no if they aren’t sure. Remember that if you say no to the system permissions prompt then it can’t be shown again, and this is embedded in a lot of people’s brains – “use it or lose it”. “Not now” is a way of taking the pressure off to stop them getting stuck on that screen, and also pretty idiomatic at this point.