We are testing for a potential use case. Another system we are testing allows you to add a text file with drop-down field values. For a second dropdown we can add a comma separate list of values that auto creates a dependent drop down. For example, we have
Dropdown A
Option 1
Option 2
Dropdown B
Option 1,Item A
Option 1 Item B
Option 2 Item C
Option 2 Item D
If you choose Option 1 in dropdown A, dropdown B will only show the options, Item A and Item B. If you choose Option 2 in dropdown A, dropdown B will only show the options, Item C and Item D. The ability to do this using text files and comma separated text files in the other system is a huge advantage for us when creating large dropdown lists.