This argument should be used on all new StreamFields created under Wagtail 3. It does add some clutter to the examples, but only using it in select cases would create more confusion...
As per discussion on https://github.com/wagtail/wagtail/discussions/7732, the changes in the upcoming release (sidebar redesign, removal of hallo.js, module reorganisation) warrant a version bump to 3.0 if we're following semantic versioning.
Add system check for use_json_field in StreamField
Change system check level to Warning
Add use_json_field argument to StreamField in test models
Use RemovedInWagtail219Warning instead of a system check
Handle unpacked values in to_python when use_json_field is True
Duplicate models and tests for JSONField-based StreamField
Add basic tests for JSONField-based StreamField
Add json_field property in StreamField to unify JSONField usage
Add docs
Don't use destructuring for kwargs in deconstruct
Add versionchanged note to StreamField reference
Currently, the label shown for a StructBlock's collapsed representation takes its content from the first sub-block of the StructBlock, which isn't always what you want. Add a new `label_format` meta option to StructBlock to allow customising this - e.g. `label_format = "Profile for {first_name} {surname}"`
Matt Westcott