We are a typical water utility with multiple departments - Operations, Construction, Engineering, Maintenance, etc. Each of these departments have personnel who consume ArcGIS Online apps for that have been tailored to their specific needs. However, there are some tools within AGOL apps (not maps) that are used across all departments; for us, these include the the Bookmark widget and the Select widget.
Every app that we publish includes the Bookmark and Select widgets. The good news is that every user leverages these widgets for their needs. For example, the Construction department has 3 AGOL users who consume the same app. However, each user creates their own bookmarks based on projects they have going on. Additionally, each user changes the settings for the Select tool based on their needs. This is also the case for users in other departments.
However, every user who has created a custom bookmark (one that is not added when the GIS Administrator creates an app) loses those custom bookmarks when the app is updated (saved) or a new app is created in WebAppBuilder for ArcGIS Online, or any time their browser cache is cleared. As a workaround, we have created an Excel spreadsheet in a shared location for storing details of every custom bookmark for every user. This allows us to recreate the personalized bookmarks for each user. This same concept applies to the Select widget. Providing a way to store a configuration file within each ArcGIS Online user account for the Bookmark and Select widgets would prevent significant manual effort and rework in regenerating these settings.
The ability to pre-populate the Bookmark and Select widgets with certain bookmarks and selectable layer settings does not allow individual users to "save" these setting after apps are updated, created, or browser caches are cleared. However, a configuration file stored within each user account could prevent users from losing their valuable bookmarks and selectable layer setting.