Great question. ALM is very important when its time to implement IT controls on the promotion of changes to production. The "standalone" model you are referring to might be suggestive of the model before its intertwined with the ALM process. By doing it this way, you are free to make changes without having to worry about IT controls. Later, you can determine which model is production and which is development. Here's a useful link that will help you understand the different strategies for implementing ALM.
Realistically any one that has been granted model builder access to the workspace will have the ability to implement ALM. There's a lot to learn about segregation of roles and I recommend reading this post. In practice, it is my opinion, which is shared by others, that the sooner you discuss an Anaplan COE the better. This will help establish an agreed-upon RACI (responsible, accountable, consulted, informed) chart that helps establish the ground rules for changes to production as well as standard definitions and processes about how Anaplan is to be governed. As you progress with your Anaplan training and certification you will inevitably be introduced to these concepts. Another way to improve your understanding is to keep asking question here on the Community site. Hope that helps!