Precheck on my Europe-US bound flights’ boarding passes does severe two purposes for me: slashes the chances for my getting the SSSS treatment at (or around) the airport gates for my Europe-US flights; and makes it more likely that my onward domestic US flight boarding passes on the same ticketed itinerary have PreCheck on them for the TSA security screening that I have to put up with on my Schengen-US-US itineraries and so I don’t need to deal with a US airline rep to get — or try to get — them to push out a PreCheck boarding pass.