Both methods have a role as both eliminate the costs associated with scaffolding or Elevated Work Platforms. It is a case of which is best suited to a site or location. Costs are relatively the same but deployment factors are the difference.
Licensing and regulations surrounding Drones are expected to become more relaxed over the next decade as safety data is obtained and reviewed. For the foreseeable future how ever, drones present a means to deal with difficul access away from the urban environment, whilst Rope Access is better suited for the built environment.
Drones and rope access are complementary as both require skilled technicians to undertake operations, the best suit can only be determined through a thorough assessment of the task, the methods to be used and the work environment.