Difference between name and field in ColumnDefs for ui-grid (AngularJS)?

Can anyone provide a practical example? From my understanding, field refers to the actual field you want to reference. That is, field should be the name of the variable (in the code) that you want to put in the table. displayName is more clear: it just specifies how the column name will be displayed in the table. This seems to be everything you need. What is the purpose of "name" then?

Here is the documentation for reference: http://ift.tt/2ybN0jU