Is it worth paying a visit to Tibidabo just to visit the church and take in the views but not go to the amusement park?
Depends how hurried you are. The views are good on a clear day. The church is a stripped-down art deco twentieth-century job that's attractive if you like that sort of architecture. But it is a little way out of the main town centre. The trip will be more interesting if you go on one of the days the vintage tram up the hill from the Avenida Tibidabo metro station is running (every day in the summer, weekends and holidays in the winter).