IDC uses a custom version of drush_choice() and drush_choice_multiple() to add some DX Features on top of them. One of those improvements is the ability to search specific items within a list (single choice, or multiple choice).
Imagine you have a long list ( > 50 items) and you're prompted to select one or more values of that list.
Imagine you're looking for values that contain a similar string in the label (e.g: "field_article_").
Instead of entering them one by one, you can filter the list by that string.