Below this, I see a list of the recommendations. This has grabbed tables that appear to continue to contain some data that might be sensitive and require classification. One of the tenets of the GDPR is that you know your data. You aren’t allowed to figure this out later, but rather you must proactively know what data you are collecting and processing.
It’s a good overview of the feature. Like Steve mentions, I appreciate this data being stored as extended properties: that way, third party and custom-built tools can make use of it. You can also script them out for migration.