This is very important to future critical thinking because this gave people evidence to back up being skeptical for future illusions that they can't immediately explain.
This same applies here with ghosts. People needed to know they _could_ be fooled, how it was done doesn't matter, because people were being scammed and were afraid of things that weren't ghosts.
Proving something is a ghost has never been done, so ghost scams is a good thing to educate people on.
In a very real sense, it is a lot like watching children (with their intelligence limits) arguing, thinking what they say makes sound sense.
This phenomenon is everywhere, including the most powerful places, and it is essentially not even on humanities radar.