It's a 3 star room in a 5-star location! If you are looking at exploring the city and enjoying life outside of the apartment, definitely stay here as the location is wonderful. You are near all important spots of Lisbon and 10-15 minutes walking distance to neighbourhoods such as Alfama or barrio alto.
However, if you are not so active a tourist yourself, I would not recommend the apartment. It's a dark-litted room, pretty small for 3 people and just big enough for 2. Furthermore, it's a mezzanine, so the ceilings are not that tall and you will be able to see the street almost at eye-level. In addition, the wifi is not great, so if you are going to have to run lots of zoom calls, the bad wifi could become a bit of a problem.

Nonetheless, it's a modern apartment and everything is on its place. There is a tiny kitchenette which is useful and works just fine. The bathroom is ok.
Once more, would recommend to anyone who is looking at staying outside and exploring the city, as you cannot bet the location. Good value for the price paid.
Thanks a lot for your help and your fast responses to our messages!