For reasons:
1) To generate some reporting in the format that the management team here is used to seeing, ie: burn-up charts rather than burn down.
2) Being able to generate a single report for all active Epics.

The endpoints documented at https://docs.atlassian.com/greenhopper/REST/cloud/ don't provide enough results to generate the results on the reports.

The information required IS available through Jira, but not all of our management team has access to/regularly uses Jira and the interface is a little clunky in terms of only displaying one epic at a time and trying to find the epic you are looking for.