Currently, the HubSpot attribution reporting tool doesn't allow for any custom properties as attribution dimensions. You can only use a selection of Hubspot created properties and UTM parameters.
We would like to be able to create our own custom properties that are updated with workflows and automation to track and attribute things like lead sources for our BD team. There are many use cases where you may want to attribute revenue or interactions based on values that don't fall within the given parameters for HubSpot reporting.
I would recommend that Hubspot make custom properties available as attribution dimensions to report on within the reporting tool. This seems like a relatively simple feature that would provide a lot of value for sales and marketing teams.