Going beyond the abstract, let's consider the practicality, utility, and features provided by these reports.
Although some of the bar charts are pretty, we were disappointed to find that they do not use responsive web design. They neither scale at all with the size of the browser, nor do the detailed data tables scale to fit the space available.
If you're curious about why a metric has a particular value, you may feel left a bit short. Many of the charts don't allow you to drill down into the underlying datasets like pivot tables would. Changing the filters on tabular data does not update the chart display, and you can't dynamically check or uncheck specific values like you might be used to doing in Excel tables.
In short, while Office 365 Reporting may offer some useful insights, it should not be considered a business intelligence...
