I have very limited experience off-road riding. If I was planning to take it up, especially a big bike like a GS, I would like to know what gets people in to trouble.
like the video says, if you go off road, you're going to fall off fairly regularly, its part of the ride.
In my younger days I rode both motocross bikes (not competitively, desert rides with friends) and street bikes. I'd always chuckle when meeting people at parties, etc. and the conversation turned to motorcycles (I may have had something to do with that). They'd usually say something like "I'd be OK with a dirt bike, but I'd never ride on the street, its too dangerous". Those of us who have ridden both get the humor in that comment, as riding off road is far more likely to involve crashing than on road (well, if you're always riding aggressively). Off road involves too many unexpected route turns, surface changes (like a 20 ft deep desert wash that isn't visible until you're right on top of it), sand, gravel, water, etc. It generally happens spontaneously without any advance warning, otherwise it would be a simple matter of taking corrective measures to avoid falling.
With motocross bikes, falling off generally meant picking the bike up and kicking it to start it up again. We'd usually keep the clutch and brake levers a little loose so if they happened to hit anything they'd rotate rather than break off, but standard procedure in the day was to keep spares on hand with tools to replace them in the case they did break on impact. We also rode in groups with backpacks of tools to do any kind of repairs on the trail (or tow the broken bike back) because we'd be many miles from civilization should anything happen.
Since ADV became a thing, and saddlebags were part of the picture, I suspect the consequences of falling off have increased, so I can't comment on that, but everything else about riding off pavement has pretty much stayed the same. I'm guessing that the level of aggressiveness we rode at on motorcross bikes was higher than what you'd attempt with a more expensive/heavy/complex ADV bike, so that is also a factor. We would climb boulder strewn slopes at 30-40 degree pitch for several hundred vertical feet to the top of a ridge, I suspect a smart ADV rider isn't going to be looking at something that challenging as a good idea to attempt, but I could be wrong. Actually, I suspect the power to weight ratio probably wouldn't make a climb like that possible anyway, but I could be wrong.
The upside of spending time riding in the dirt, you get a natural feel for how the bike responds when it loses rear wheel traction (or both wheels sometimes, like in deep sand) and it makes you a better street rider when the bike momentarily loses traction.