It is a relatively easy route to operate I would guess

On JFK-LCY, when the flight is normally full, it is still 32 passengers maximum with 3 cabin crew. It is also a sleeper service so not a lot to do except to wake passengers up and a rush to provide a cuppa tea prior to landing.

On the LCY-JFK flight, this is not normally full

Cabin crew also get one night overnight's allowance for staying over at a LCY hotel prior to the flight.

The only down side is the lack of crew rest area and being bussed from LGW to LCY to start and end duty.