One reason I have provided this info when traveling internationally is that if there was a flight delay, the host would have no way of knowing my arrival time. I don’t have any way to contact the host while I’m still in the air. Many international flights don’t offer wifi connectivity and even when it is offered, some people like me do not want to pay for it.
@faheem : People in the USA & EU have a higher desire to protect privacy. I think if you explain why you need this information like you did here, they might comply.