Not to long ago, Microsoft introduced the column type “Location” in SharePoint Online. This is a great addition for business solutions. From a PowerApps perspective, the usefulness is limited to showing data (Country/Region, State, City, Postal Code and Street).

So is it not possible at all to update a location field from PowerApps?

See PowerApps in action on multi-step Business Workflow Processes, that isn't hard-coded.