@Cathy463
Yes, it's true that contacting guests directly via text or WhatsApp or whatever might be an easier way to reach them, but he fact is that we are supposed to keep all communication via the Airbnb messaging system because, if anything were to go wrong with the stay, this is then counted as evidence, whereas messages off system are not necessarily counted.
It might seem a bit paranoid, when you are just sending directions or checking to see if the guest has everything they need, but if you get a guest who later turns out to be problematic and makes false claims to get a refund or whatever, you then have a back up.
I had some awful guests who were very dirty (to the point that it was detrimental to other guests staying at the time) and also caused some significant damage to my house. As soon as I politely asked them to please be more careful (never even asked for money for the damage), they became very hostile and then left me a horrible review with very low ratings, including 1 star for communication.
An Airbnb rep decided to remove that review and the ratings largely based on the correspondence between me and the guest. He said he could see from the messages that I had been in constant communication, responsive to all their needs and consistently polite, so the 1 star for communication was clearly out of line and retaliatory.
Use other forms to message guests if you must, but it's still preferable to have a record of discussions on the Airbnb system.