Clear "Settings" app data. What happens?

[EnzoS]

Out of the blue, the wife's Galaxy J7's mobile and wifi data usage can't be checked. Phone displays a popup "Settings has stopped. Open app again". I've tried all the suggested fixes EXCEPT clearing the settings app's data and a total wipe (factory reset). The absolute last resort is a total reset so I'm ready to clear data from the settings app. Question: what's gonna happen when "clear data" is tapped? What settings or configurations will require re-entry to get back to normal???