We just started using NetSuite a few months ago, so I apologize for any confusing terminology from my side. We were allowing the default behavior of using the Name as the Employee ID (not internal ID, which is hidden on the new employee record screen). We have a couple people in the company with the same first name, middle initial and last name. We found that in these lookup fields like the Supervisor dropdown, we had no way of distinguishing who was who. So we switched to using a numeric value for the Employee ID instead. That created the concatenated Supervisor field, which is sorted numerically, making it useless for us.