Admittedly, the most stressful part about a project such as creating a new work space or similar, is keeping on top of everything that requires attention such as organising contractors or ordering supplies. With a project manager to take away the responsibility of the general day to day running of room refurbishment it leaves the client free to continue doing the job that they are hired for.
Having someone whose sole job is to ensure that the specialist room is being constructed to excelling standards means that there is no distraction and full attention can be given to that particular project. You’d be surprised at how stressful project management can be when trying to juggle it with other day to day work tasks so it is a sense of relief when that part is done for you. All the client has to do is ok the designs and plans then sit back and watch the creation come to life.