We are a family of 4 traveling to Barcelona. I'm wondering if it's a good use of money and if it's helpful to buy the Hola Barcelona card to get around? We will be staying in Plaza Catalunya and going to Camp Nou, the Montserrat Monastery and then around town to see La Sagrada Familia, Casa Mila, Park Montjuic, and Barcoloneta Beach area. Will the Hola card work for all of that and is it useful? We will be in town for 3 days of sightseeing. Thanks!