Removing the gateline at one end of the shuttle certainly makes it easier for passengers (often with their hands full of luggage), and allows staff to be concentrated at the barriered end to help with tickets and payment.
Another not-fully-barriered airport people-mover system is the
AirTrain JFK, which serves the various terminals at the New York John F Kennedy International Airport in a loop and has branches to Howard Beach and Jamaica stations on the NYC Subway (and also Long Island Rail Road at Jamaica), which are the only stations with gatelines. The lack of gatelines at the airport stations is a necessity (unlike at Luton), as the AirTrain acts as a free shuttle between terminals, car parks, etc., while passengers using the AirTrain to travel to/from the airport
are charged $8.50 to get through the gatelines at Howard Beach or Jamaica. Many years ago when I rode it from the airport, upon arrival at Jamaica I had to queue up at a bank of ticket machines inside the gateline to buy a MetroCard to exit, but these days you can also just tap through using contactless.