I have lots of data in Microsoft Access databases, and it would be great if Access was supported as a data source for apps.
Microsoft Access database shared on OneDrive can be a really good start point to build hybrid solutions (Desktop-Cloud-Mobile). At least a more robust alterative to Excel files.
Microsoft Access has some unique features and so far is the more complete tool to build RAD applications.
Hope to see this data source connector as soon as possible.
I would also suggest you look into Access Web Apps, which can be integrated with PowerApps.
The limitation is that they need to be hosted in SharePoint.