The intended purpose of the feature is to set the default reminder for new meetings you're creating and inviting other people to. Which is not how people interpret it, and not how it should be anyways. I shouldn't be able to set reminders for other people, and they shouldn't be able to set them for me.
Internally it tends not to be too noticeable because most people don't change this setting and it seems to default to 15 minutes, so it just happens to work out most of the time. I had a coworker who for some reason changed this to never, so every time she invited me to a meeting I would be late or miss it.
And then for some reason, external invites default to never all the time. But even if they fixed that, they really need to completely change the purpose of the feature. It should only be a setting for our own calendars. It shouldn't have anything to do with setting what the reminder should be on other people's calendars. That shouldn't even be an option when setting up meetings.