If most of the works have to be done in a sequential manner (if there is zero possibility for parallel execution), orchestration is the way to go. If there's a need to keep the control flow logic centralized, orchestration is the way forward. If there are hundreds of microservices participating with different control flows, centralization is preferred. The mantra of distributed deployment and centralized management is getting fulfilled through orchestration. If the decoupling is not a strict mandate, the orchestration method is the widely-used one.