Very interesting apartment! It's in a perfect location (and you cannot find a better spot to stay in Athens), the view is truly special and you have what you need in the apartment.
Downsides are a pretty slow wifi (I managed to have successful online meetings, but expect freezes) and uploading ~50 iPhone photos easily take 5-6 hours. It's 0.4-0.5mbit upload. The shower is also quite bad (nearly impossible to hit a nice temperature with a good stream). However, this is not the owners fault - you're just staying in an old area.
A wonderful Airbnb. If you're here for a vacation or a stay to see the city, you cannot find better. If you're here for working remote, you should consider if you might want to use a co-working space instead.