Costs associated with Data Pipeline S3Datanode staging

I'm confused about how staging of an S3Datanode is billed when done as part of a ShellCommandActivity with the 'stage' property set to true (i.e. I do not have CSV data and am not using a CopyActivity).

Here is an example: https://docs.aws.amazon.com/datapipeline/latest/DeveloperGuide/dp-concepts-staging.html#dp-concepts-datastaging

I see a 'runsOn' option for S3Datanode. Is that how you control the resource used to do the copy? That would make sense since it seems that is how CopyActivity works. I'm just not sure because I don't see any examples doing so.

To wrap up, is the idea that I can use a cheaper instance for the data staging to save money? (I understand that the staging also simplifies my workflow but just wondering if there is a cost incentive as well).

https://docs.aws.amazon.com/datapipeline/latest/DeveloperGuide/dp-object-s3datanode.html