This is fascinating. I had no clue you could get paid to do this.
Many generations ago, the nobles would be able to pay to be trained by experts in their fields, which gave them an edge over the peasants. Fencing, other combat, literature/reading, and military tactics ... those were some of the things they would pay gold to learn.
Nowadays, it looks like things are different. You're still teaching tactics, only it's a bit more digital. And I doubt all of your clients are loaded, but there are definitely parallels (loose parallels) that could be drawn.
Neat stuff!
Odd comparison, but I see what you mean. Thankfully in our digital age, resources are everywhere for those keen to learn, just gotta know where to look.
Unfortunately, it also sometimes does mean the wealth and spread of misleading or inaccurate information, such as old wives' tales circulating around facebook or popular social media.