To understand the impact of logging interactions on won sales deals, a report that includes "Closed Won Opportunities with Activities" would be most appropriate. This report type allows for insights into how recorded activities (such as calls, emails, and meetings) correlate with opportunities that resulted in closed won deals. By analyzing this data, Universal Containers can identify patterns or trends related to customer interactions and their effect on successful sales outcomes.
For additional details, refer to Salesforce's documentation on Reporting on Activities and Opportunities.