Export/import and change data source as long as the source has the same setup.
Edit the data source and keep the app as it is. Reuse the app in a sense. As an example you have a SP product. It is installed on a customer online tenant. Then you create an PowerApp for the SharePoint "list/setup/product". New customer, same SP product installed. Then export/import the app. Change data source and publish to the new customer’s employees.