"The grass is always greener on the neighbor's yard.."
With other words and more to the topic.... there is no (real) oath of secrecy if there were, you wouldn't know.
Let me share a story (again) of how value is added to some stuff...
Back, way, way back around 1500 and some, there was this pope, a cool, smart guy Pope Pius the 3rd who was convinced by the diary and influence of its predecessors that magic should be more restricted, common folk should not know much about their power so he made an agreement and paid with his life ... the subject of the agreement was to restrict and control all magic crafts along with some healing methodology.
The wheels in motion, Pope Pius dies and his plan is starting to be implemented.
Because the catholic church learned from previous experiences (betrayed by templar order) got smarter and remembered the golden rule, "don't use conflict" but convert (lightworkers, transforming the bad negativity into light) so, they recycled the idea of "build on top of their belief and convert it" -- build a church on top of a pagan temple, the energy is still there but converted and manipulated.... so, that's what catholic church did...
First they gathered all the cool pagan writings, knowledge, manuscripts, around the world and "translated" into various versions and that's how priests had become not only scholars (spreading the word of God) but magic practitioners too.
The ones who translated knowledge from hebrew, sumerian, tables, (the first grimoires) had to corrupt the magic they discovered so it would not work... Take the Lesser Key of Solomon, there are 72 "demons" who build the Great Temple... the knowledge is made public, was/is and will be studied, yet nobody ever successfully build a garage not to mention something more... (and few understand why)
Anyway, long story short, what magic content (books, grimoires, real shit) is infact corrupted and fake for the most part... 90%.
Here's the "devil's trick" how to add value to nothing useful? This was the question and the robe-scholars come up with a plan, "let's convince folk, magic is in the fake books we plant in churches, monasteries, abbey around the world... and hire mercenaries, vikings, thieves to pillage, rob, still and kill for them and we also pay them to sell their books to church...
Why this plan worked? Because man in robes were ones who knew to write, read, teach... the word of God... as a representative to God's will, these guys had a lot of influence...
Bottom line, make something hard to reach, inaccessible for the masses and all will want it... it was in human nature.
Devil's strategy of marketing...
Something which is indeed under the oath of silence is unknown by definition, but to attract we can use this "attention suckers" words like "hidden knowledge, known by the elite only" ... stuff like that and for the most people works just like that...
The best marketers was the catholic church and its emissaries ...
Magic works only when belief is strong and when focus charges the subject of the magic... if is unknown, there's no awareness of it, no focus, no energy... Belief move mountains...
Secrecy build interest, hidden builds interest, elite builds interest and where focus goes energy flows... it is a game of illusion for the masses.
But many seam to awake...