If you need a place in a great location close to tourist sites, and don't plan to spend much time in the apartment, and are not bothered by the very loud noise of the street or neighbors, then the apartment should suffice for your needs, but it will certainly not add to your experience of the trip.
The place is run down. It needs to be repainted and updated. The bathrooms are old - the shower-heads spray water everywhere. The second bathroom is tiny. The apartment is noisy. Yes, it is on a very busy avenue. But we lived in another apartment also on a main avenue in Barcelona and the noise was incomparable. Because the windows have not been altered or sealed. Plus you hear neighbors as if they are in your apartment. I would say that you would not want to hang out in this apartment for any prolonged period of time. It is not a pleasant experience in and of itself. You will have a perfectly acceptable bed and the linens and towels are fine. There is a small kitchen in case you want to eat leftovers from a night out at a restaurant. But you are not going to want to be chilling in this apartment. It is not a good value. Yes Barcelona is expensive and if you need something in a pinch last minute it will work for you, but if you plan ahead you can find places that will make the overarching Barcelona experience more pleasant.