This article, although informative, is simply regurgitating info that has been stated before.
IMHO (so long as your budget allows for the use of BH209) I would say that you should use whatever shoots best out of your rifle with your chosen projectile. I would also add to the list other manfs. of black powder and Pyrodex RS and P.
My experience is that in every rifle so far that I've shot BH209 out of (I'm still not done testing) I can get better accuracy with some other powder. Velocity also IMO means little. It just means you'll miss your mark faster!
As for the cleaning/swabbing, whatever you call it, that means diddly squat in a hunting situation where I have rarely needed a second shot. And if I do I have ample time to swab the bore if I want or I'm able to load a second load without an issue.
So it doesn't matter to me what the so called "experts" say on this topic.