The owner does not live in Lisbon so it's likely the apartment is permanently rented to Airbnb guests, since you will be dealing with those who seem to be the owner's employees and not the owner himself. Aside from the moral questions about apartments such as these which drive up rent prices in major cities, since they are taken off the market for actual locals to rent, issues can come up such as when our host/contact requested we receive a water technician, or vacate the apartment so that she could be present to receive the technician (no urgent problem to solve, just a check-up). As this visit was in the morning with no specified time, and we were warned just one day before, this was very inconvenient, and a totally inappropriate request for Airbnb guests.
The pasteis de nata and porto to welcome us on the first day was a lovely touch, but sufficient toilet paper in the bathroom for our stay and paper towels in the kitchen would have been more appreciated!
Communication was also limited as the owner never responded to my question about parking, so we ended up in the closest parking on the first night which was obscenely expensive. The contact who we did the check-in with directed us to a better parking, this however could and should have been answered before our arrival.
Other than that, it cannot be denied that the apartment is nice and in a central and lively neighborhood.