The apartment is good enough. It has new fixtures, wooden floors, warm showers, a lift, a small balcony, etc. It was missing a few things that would been helpful, like a dish drying rack when there is no dishwasher. The apartment is near Sagrada Familia, but the neighborhood is a bit sleepy overall and a long walk to La Rambla (though near to a few metro stations).
The host inspired much confusion after sending an email saying I should provide her with all of the passport details of my family members and pay directly to her a "tourist tax." Through communications with Airbnb, I learned these are apparently Barcelona legal requirements, but the request wasn't originally explained that way and just seemed so dodgy. The host also wanted a security deposit paid directly to her, instead of through Airbnb, which also seemed dodgy. Ultimately I didn't pay it. In the end, it all worked out fine; I just had to sort it out with Airbnb Support.