Newcastle don't have the squad to compete in the league, Europe and the domestic cups. May the fatigue and build up of niggling injuries derail their season.
They'll want CL progression, but they know they're not likely to get further than the first knockout stage at best. Good experience for the team, but they're not likely to qualify again this season, and the League Cup might offer them the chance of actual silverware.
I think they'll go for it, over reach themselves, and blow themselves out in the league; they will probably sacrifice the FA Cup.