One usecase for editable datapage usecase can be If you need to fetch a record from the database by sending the key column as a parameter and updating the requried values on to the data page by performing obj- save on the data page.
In that case, you may want to know the difference in Read-Only and Editable mode of data page and chose which could be best option for your application.
Read Only – Prevent the data page from being modified, except during page load and post-activity processing. The data page displays in the Data Page list on the clipboard.
Editable – Allow the data page to be modified. The data page displays in the User Page list on the clipboard.
So, when a data page is configured to be read-only, you cannot really modify the properties on the data page during the case process unless there is a page load/post load processing in data page configuration. If the data page with read-only mode is attempted to modify without any of the above mentioned conditions, then you might face an error saying readonly data page cannot be modified from ClipboardImpl class.
Hence, if your requirement is supposed to modify the content in data page during processing, then you can go with editable data page.
Editable data page behaves mostly like top level data page with some advantages(i.e. Loading strategy, sharing data, parameterized data page etc). So most of the things can be done using editable data page can be done through clipboard page. Only thing when you want share the edited information of one thread to other thread, this can not be done by clipboard pages.
If the user wants to modify the data then Editable Data Page is the only option, but these changes wont persist into the database. Apart from this i couldn't find any specific usecase for this functionality.
One such scenario I thought is "Editing records from a grid".
1. We have to show multiple records in a grid (only few columns). The count of records can be high here.
2. We can create a data page that gets loaded using RD
3. Now when I want to edit those records, I can use 'Edit in Modal dialogue' option grid which allows me to fetch the entire record on to Clipboard and allows to update. To get this done, the data page has to be editable.
Now I can reuse the same data page at other places as well which is not possible using normal clipboards. This can still be achieved with other approaches but if you want to reuse the data page, then editable DP makes sense.
I don't think there is a scenario where only editable data page is the option. All use cases mentioned above can be achieved by using normal user pages (top level clipboard pages). But the intention of introducing editable data pages is to create top level pages declaratively rather than using activities/data-transforms to create those pages. By using these editable data pages, PRPC engine decided when to create those pages rather than user trying to create those pages as part of pre-processing activity/data-transform of flow action or other scenarios!
I see you have been asking this question since June. Let's step back, can you help me understand the business problem you are trying to solve where this matters? I can't think of a case where it is the only option. There can definitely be business cases where you wouldn't want it read only, but I don't know of a place where the system doesn't allow you to call a read only page. That said, I feel like a vague "no, I don't think so" may not be satisfactory if you have a specific concern that is driving the question.