As an example, I just came across the below column Ticket Created- Week of Year. Greatly appreciate it as I am using for differences however it doesn't work well at all for presenting/sharing dashboards. Especially with this work from home policy, many executive teams are asking for a comparison of ticket volume compared to a point in the past for the stay at home period.
Showing an executive member a graph like the below doesn't really convey the information easily so I believe I'd always have to use a custom attribute. Zendesk even seems to convey that thought process through the average tickets created by day of week. (You don't see the default dashboard for Monday as Day 1 as an example.) Secondly, custom attributes don't do date ranges so it becomes a static comparison with no ability to change where the start point is.