The new Universal Reporting feature looks a lot like the existing Dashboard tab on projects. Which makes sense because it is the same feature, well almost exactly. So you might ask yourself: why would I use Universal Reporting instead of just having several dashboards?
The reason is about comfort. It is easier to have everything in the same place. In my case, even for charts specific to a project, I moved them into a Report for easy access.
The nd reason is that it allows you to build charts with source data coming from various projects. For example, you can mix that data if you have design requests inside a web-design project and print project.
The rd reason: you can put next to each other charts using different sources, to compare them or easily analyze them. For example, spendings on the left and earnings on the right.
Finally, the th reason: Universal Reporting allows you to share a dashboard without sharing access to the projects. The dashboard will contain exactly the same data as you would see them, without revealing the exact content of the projects!
Bonus from @LEGGO: you can apply the sweet new dashboard icons as well as provide a dashboard description that highlights the key items to absorb from the visuals. You even gain the ability to Favorite a Dashboard within Reporting.
Any other reasons I missed?