I'm not sure if blockchain is required for bookings, already quite a few webservices emerged offering a marketplace to bring artists and promoters together. However, booking an artist for a promoter is generally a manual activity not because it cannot be automatted but because the promoter may have some artists in mind, but can be influenced to book some other artists when sold to him/her. That is the profession of a booking agent. To know what the promoter likes, to offer the artists(s) at the right time, to know what artists can perform together in the same room / party at the same night. The promotion of artists is like selling expensive products to B2B players, this cannot be done automatically, at least not for those who make a living out of performing. The fees are such high that it is one of the biggest expenses for a promoter, ie it requires emails, phone calls and such like to get to a deal. Once a deal is made, the rest can be done automatically, ie generate a contract etc. The logistics like travel etc, could potentially be done automatically, but also here the schedules of an artists are generally not set in stone and dynamic, and feedback from the artists or manager is generally required to make the right arrangements. Blockchain could help in sharing the contract, schedules etc, but can not become the prime automation service/DB to cover the whole process of booking and management.