Great for training spatial awareness!
In the grand old days of instructing it was necessary to hold at least a IMC rating. To upgrade from Assistant Flying Instructor (AFI) to Flying Instructor (FI) it was necessary to undertake an upgrade test. It was commonplace prior to this assessment to complete a course to teach applied instrument flying (IMC rating). On day one of my course the FIC instructor asked me what the main basis of my IMC training was: "NDB sir" I replied. His comment: "thank God for that, you will have spatial awareness, the VOR/ILS lot never know where they are".
What tells us much of yesterday times is the term given to the NDB onboard equipment that is: Automatic Direction Finding (ADF) radio. Hardly that of course in todays meaning of the words.