Answering guests in their own language
A guest writing from Belgrade, Moscow or Berlin is not going to switch to your language to ask whether you have a free room.
Along the Montenegrin coast this is not an edge case, it is most of the summer. Enquiries arrive in Montenegrin and Serbian, in Russian, in English, and in whatever the guest happens to speak. Every one of them is a real booking if it gets a real answer.
Replying in the language the message came in does two things. It removes the small friction that makes a guest move on to the next listing, and it signals that the place is run by somebody paying attention. Both of those matter more for a stranger choosing between apartments than any amount of description.
A system handles this better than a phrasebook because it is answering from the same facts either way. Your rooms, your rates, your availability and your rules do not change with the language, so the only thing that changes is the wording. That is the part software is genuinely good at.
Where it stops is anything with nuance: a complaint, an unusual request, a negotiation over a long stay. Those come to you, in whatever language they arrived in, and a person answers them. The system is there so the routine enquiries never sit unanswered waiting for one.
Tell me what you are losing.
Thirty minutes on a call. I will tell you what we would build, and honestly whether it is worth it.