to be fair, most of the practices contained in BD pre-date BD itself considerably - it doesn't claim to be exclusive in regard to it's practices. in simple terms it's the start of organics, as a modern movement. with added weirdness at first glance..
the preps sound weird ofc, but for example: one of the cow-horn preps adds silica to the soil in an entirely organic way (some peeps pay good cash to get chems to do this..), as well as having superior micro-herdage.. all the preps have similar properties that undoubtably make a difference to a plant/garden etc in many ways(and many MJ growers do after all pay for additives that add just a few percent to yields etc). now, what most folk see as mysticism does have another layer..
the horns for example, which are surprisingly easy to find in the world of farming
(had a chat with a BD farmer about this recently, a very intelligent guy whom i know well and trust).. as a cow ruminates, it's horns are heated by the friction in the skull and constant cycling of warm air, this produces a reaction to the sillica within the cavity of the horn, turning some of it gaseous, and meaning it wil be more readily available as a nutrient in compost later.. this is the short non-scary version, but i've heard many similar examples through my work.. now, many things are buried/planted/etc on given days, which can seem weird, but i think it's well established that planting by moon cycles does actually work, and yet people question the involvement of the moon, or other bodies, in other parts of gardening such as composting and use of preparations.... hmmm
a lot of BD is really quite logical when you look at your activity holistically and tune in a bit