@Julia2500 Yes, and in fact, as a host I've found this useful. If I haven't heard back from a guest after sending them necessary info through the Airbnb messaging, or the coded email address Airbnb uses for hosts and guests, , I've texted them to let them know I've sent them a message. Lots of guests seem not to check their Inbox once they've booked, and may only bother to get back in touch a day or two before arrival.
However, if guests are texting or phoning you, you can just reply that it's recommended to keep all communication on the Airbnb messaging system and to please contact you in that way instead of text.
There's things that I find don't have to be on the system, like a guest calling or texting me let me know they've arrived in town (I pick my guests up at the bus station). But any arrangements for the stay, questions and answers, and anything that might prove contentious in the future for which you'd want documentation, keep on the messaging.