Pros:
-Location - hard to think of a better one
-Very responsive host, thanks Ellen
-The bathroom and apartment are very clean overall
Cons: (those are disadvantages to me, probably someone else will be absolutely fine with that)
- The room has no windows (just walls) and no proper door (a folding door instead), and no fresh air. It felt very uncomfortable to me being there.
-Furniture looks and feels like it was taken from waste, doesn't add more comfort to windowless and doorless room
-It was very cold inside (I felt warmer outside, Feb time, though), I was sleeping dressed and under two blankets.
-You'll have 5-6 neighbours trying to use the same bathroom in the morning
I personally will not return there, but this is probably a reasonable choice value-wise.
At the end of the day, Barcelona is a beautiful place!