The NDB, as stated earlier, can be a real aid to understanding SA, and flying them, sharpens exponentially the skill set for IR flying.
However the accuracy of the information an ADF can give you can be very inaccurate.
On long oceanic trips the least valuable aids we had were the ADF and HF transceivers.
We maybe should wring our hands wishing we had the radio ranges back...after all, all you need then is a cheap portable AM receiver stuck to your ear.