I agree that telling me exactly where I can change it can be helpful, although I'm also sure I won't remember that.

But we're comparing to the case where it just says "No", in which case "Not now" at least tells me I can look up how to change it later now - or more importantly, that I don't need to give this further thought now.

Yes, PMs (or anyone) making software doing dumb shit is dumb anyway, but that also holds true if it were labelled "No".