If you run tableau in an enterprise environment you will likely have a lot of c level executives, global sales teams and more relying on tableau to be available outside of your local business hours. This means any maintenance needs to be planned and communications sent out to all stakeholders.

If reloading was an option then there wouldn't be downtime, and I wouldn't need to schedule a maintenance window for something as simple as updating an email address. The idea being that if there is a config error during a reload, the system just continues uninterrupted with the original config. If I have to stop the system completely in order to run the config sanity checks when it starts again, the potential for prolonged downtime is much greater.