In the past I believe I had a text area field and I converted it into a smartdoc field that was able to be used in a lookup. With all the capability a Smartdoc field currently has I am sure it is not as simple of a feature addition as it may seem, But Text Area Fields have limited capabilities for formatting.
I would like to use Smartdoc fields that have checklists and formatting as a lookup to display the value in a different app. Currently I have a smartdoc field that has values in it per client, per record. If I have an update I would have to either create a CSV File with matching titles and do an import hoping the formatting stays the same or use an automation to update every record. If I Bulk update the column with the paste feature it spreads the values out across multiple records so that isn't an easy option for updating values. However if I had those records linked to one profile with a lookup field then anytime that field value is updated it would reflect across all the connected records seamlessly.
Not a high priority compared to other requested items, but would be nice in the roadmap.