A + inf vs. imperative

Hola Julia

There isn't any specific context to use this structure as a command, really. It's an option that is a bit more generally directed to more than one person I would say, although you could also use it for "tú". Maybe in more desperate situations where you actually need to shout the order? a typical case is what is shown in the example about the kids when they are noisy. 

Saludos