Not sure if Marco does exist, or if the real owner is named Marco....because I never met with him.
Indeed, you would be renting "one of many" apartments. The level of service is really not worth the money !
Our stay was at best "OK", but we've faced too many obstacles and problems for the high price we paid to be satisfied. We ended-up calling a customer service "MitHouse" and felt like it was not at all an Air BnB experience. From deteriorated furnitures to the management of "virtual keys" (if fact it's an App that you need to download and that eventually works sometimes...) . Presented as a way to "facilitate" the access to the appartement, it was the absolute opposite !! Each guest would eventually have to register into this App and be asked for passport and facial recognition pictures (no, ......you're not accessing Fort Knox.....:-). ).
We had to waist a lot of time, insisting to get cards to access the building with certainty (as App wasn't working and we didn't want to stay out in the cold for too long....), .the roller blinds of the room broken, the warming system not functional at the beginning, the access to the terrace that we had to ask (beg) at several occasions before we get satisfaction. Even the day we left, we wanted to access the terrace to have a last view to the sunny Madrid ...and it was not possible.
I'm not even mentioning details regarding the poor status of some furnitures and equipments that were far from the ideal pictures, the lack of glaces for wine or the "bare minimum" to cook or get a coffee (no salt, pepper, oil.......even the boiler was leaking (which can present risks of electrocution).....
I'm sorry to say but this is not to the standard !!
The spirit of Air BnB is to have a local experience with the feeling to "leave in someone's flat", and expectation of a personalized experience and service. We had bad experience, feeling that we were "one of the many customers" of a big company, renting many flats and not considering host experience as a key priority at all...but rather looking for "milking" hosts, get their money and get them out at 11 am whatever happens.