In Intacct, Dimensions provide varying degrees of functionality.
Entity/Location and Department are rather powerful — you can always find them as a filter on standard reports throughout the Core Application.
Most are associated with a particular Module. For example, you’ll find Customer, Project and Item are key filters in the Order Entry and Accounts Receivable Module.
Intacct itself and most VAR’s have “best practice” assignments for each Dimension. While providing guidance, it may not be the “BEST” functional fit. I reviewed one implementation that followed that guidance for Project. Good design — but it could’ve been great if Customer had been used instead, with Project then used for case. Please think functionally!