Should we import applications via an application instead of the Designer Studio?
In my opinion yes. But this is mainly influenced from a partner perspective who has to deploy the same process to multiple customers who require that these kind of things are documented.
What would be the benefit of having an application:
Creating a snapshot of the relevant elements before the import and after the import will allow us to change some settings back, if there was an issue. For example, if a business entity is deactivated in on database but not in the other. Or when the application group, application supervisor should be different etc.
You can find the details in this post:
Import applications using an application