Sadly I have to say that my and my friends' experience was not pleasant at all. I could overlook all the many requirements to actually book it (they ask for pictures of all of the visitor's documents and a lot more information, like the city of birth, etc. so the booking process was way too complicated and took a long time), but them accusing us of stealing/losing/taking their electronic key was next level... Sad really because the place was very cute and we liked it a lot.
So long story short, upon arrival, tried to use the codes sent to open the door (they didn't work at first, so we had to call for them to open it remotely) went up to the apartment saw a sign that was talking about an electronic key but no key was present, we did not think of it much because we had the codes to open the doors. After check-out, I received a message asking about a key and an e-mail from Airbnb that they are asking us to pay for the lost key. After trying to explain the situation to the Airbnb resolution agent it was still decided that we should pay for a key that we haven't even seen.
I really do hope that it's a mistake (the cleaner took it maybe, etc.) and that they are not trying to scam tourists but I thought I should implore caution.
Also sad that Airbnb is siding with the host on this one. We feel it is very unfair to accuse us of something we did not do and expect us to just pay for something we did not even use..
Also a tip for you: whenever renting an apartment, take pictures before, just so you can prove yourself later if needed. (sadly we didn't take any)
Be safe out there, fellow visitors!