Transparency and trust are vital to the Airbnb experience. People rely on information in Airbnb profiles, reviews, and other verifications when deciding whether to host or stay with someone.
We require Airbnb reservations booked for personal travel to be booked by the person who's going to stay at the listing.
Instead of making a reservation for someone else, consider referring them to Airbnb. You can refer them to Airbnb directly from your dashboard by clicking the Invite Friends button. When a referred friend or family member successfully completes a qualifying reservation, you’ll earn travel credit.
For business trips, Airbnb allows designated bookers at companies enrolled in Airbnb for Work to book trips on behalf of others. If you book travel for your company, find out more about booking for your team."
Source: https://www.airbnb.com/help/article/427/can-i-book-on-behalf-of-a-friend-or-family-member?ibbe=1
The reason for this is that the guest that requests the booking has been fully vetted by the AirBnB system through various methods. The people you're booking for are not. It's for the safety of the host. Think about it: if you were hosting someone, and people who weren't the person you were contacted by shows up, how would you feel?