The file description is still displayed even if the setting Display resource description is off.

Replication:

1. Create a course and turn edit mode to On.
2. "Add and activity or resource", then "File"
Set the following fields:
Name: {whatever name}
Description: {Whatever description. non blank}
Select files: {embeddable file such as an image}
Appearance > Display: {Embed}
Tick/enable (any) below
-Show size
-Show type
-Show upload/modified date
Appearance > Display resource description: un-check/disabled

RESULT: The description is displayed.