As a marketing manager I want to track assets where I don't have access to full HTML5 capabilities.
There are certain web assets like Ads and pages that don't allow for java script functionality, that can currently not be tracked by just using HubSpot tracking tags.
This also goes for the practice of daisy-chaining several tracking requests as is common with all major AdServers.
An alternative solution is to use Google Analytics tracking (https://developers.google.com/analytics/resources/concepts/gaConceptsTrackingOverview) which offers the more old school approach of 1x1 pixel tracking with attached parameters.
This does however add another level of complexity to tracking assets that holds marketers back from becoming more data drvien.