ArcPro should give users the ability to add descriptions for your fields. The user would be able to add a description upon field creation or in the "Fields" menu after the fact. At the company I work at, data gets pushed into some of our fields from other databases and data tables. There are times when we need to find out exactly what database the data is coming from and the field header in that database. The "Field Description" could describe what database that data originates from. Currently we keep track of that using a excel spreadsheet but it would be much more efficient to have that within the feature class. Another example is if we have a numeric field titled "OilVolume" the description could contain the unit of measure (gallons, barrels, liters, etc.) within the field. There are many other things that the "Field Description" option would be helpful for and i think a lot of people will agree.