We really like using the Story Map Series template for situations where we've got a lot of data layers to show but want to break them up into manageable groups to make it easier for a user to understand. So we put different groups of layers in a web map for each tab e.g. environmental, partnerships, transport etc and because they can be synched then we get a nice experience for browsing through the data - certainly preferable to scrolling through a long list of layers in a table of contents.
What would make this even better would be if there was some way to pass across an extent that we'd like the first map tab to zoom to in the same way that you can for a Web App Builder app (https://doc.arcgis.com/en/web-appbuilder/manage-apps/app-url-parameters.htm), either by passing coordinates of an extent or specifying a map feature to zoom to.
I know that ESRI have just released the ability to use main stage actions within the Series template but this would require us populating a list of every single feature in our map layer that we might want to zoom to (400 records in this case) and still relies on the user clicking on the correct one. If it could be passed to the app via the URL instead (obviously relies on the entry specified being a map tab) then we could very easily link to it from our content management system where there is a page of details per map feature.
I guess this might be achievable if we download and customise the template but would be great if it was done out of the box.