I’ve haven’t stayed there, but that hotel is way out of the way of the places you want to visit in BCN. I wouldn’t stay passed the Sagrada Familia, and prefer staying close to the Eixample or Plaça de Catalunya, both being just north of the Barrio Gothic while not as crowded. You can easily access all three lines of the Bus Turistic from there, which is the best way to get around the city.
To answer PP‘s comment, the Bus Turistic lines does not go further than Port Olympic, which is 50 minutes away from the Hilton by foot.