Hello all,
The API team has added display_value to custom fields.
display_value is a read-only field that will always be a string. For apps that use custom fields, this is a great way to safely display/export the value of a custom field, regardless of its type. We suggest you start using this field in order to future-proof your app for upcoming upgrades to Custom Fields.
For example, if we release a custom field that is a complex list, the value of the custom field might be returned as an array with unique types (["Item 1",2,$3.33]), but the display_value will stay a simple string representation of it, like: "Item 1, 2, $3.33".
We hope this makes your life easier!