Microsoft told us some months ago that they would block the creation of new eDiscovery cases in Exchange and SharePoint. A course reversal has happened because of the humble discovery mailbox, which Exchange uses as a target for eDiscovery results. The block has lifted for Exchange but remains for SharePoint. It will eventually happen for Exchange but Office 365-wide functionality is better than workload-specific features.
https://www.petri.com/microsoft-reverses-ediscovery-decision
