The function of the Automation node license is to determine whether you are licensed to use it. In fact in your license file there is a feature that says whether the Automation Node is enabled for the license or not (see screen shot below).
I don't think that's the question you really wanted to ask. I think what you really wanted to ask is why would you need to control how many users access the Automation node. This could be for many reasons, sometimes you will allow your users to access the Automation node, maybe they need to check a model, see some analysis or perform some validation. Or maybe they need to export some data, look at some dashboards or review scenario logs. Or sometimes you will have an Automation node that is not accessed by users since it runs all scenarios in the background and persists all the outputs to a database where dat ais then used by other systems.
