There are a few limitations when accessing dashboards and reports from the mobile app, but since this app is used for on-the-go access, you need not have all the features of dashboards and reports on a small-screen device.
Here is a summary of some of the limitations:
Users are not able to create and edit a dashboard or report
The report format may be ignored, and drill-down may go to tabular, summary, or matrix reports
The drill-down setting in the dashboard component may not work
The chart added in the report may not show up
Chatter feeds are not available in dashboard and report