Has Freemasonry adopted the procedures of the operative Mason and were there important  reasons for such secrecy at an early stage  and for it to have had so great an impact for so long,

We have a record of a non-operative  "being made a Mason" in 1646.  He was  Elias Ashmole, an officer in the royalist army, captured at Worcester and in October 1646 he was on parole in Cheshire. Ashmole would later become a member of the Royal Society and founder of the Ashmolean Museum among other achievements.

  Ashmole was about to ride south to London. The country  was , as events of the next years would show,  one step away from anarchy.
Here  is the entry in his diary: "I was made a Free Mason at Warrington in Lancashire, with CoIl: [that is, Colonel] Henry Mainwaring of Karincham in Cheshire. The names of those that were then of the Lodge. Master Rich [that is Richard] Penket Warden, Master James Collier, Master Rich Sankey, Henry Littler, John Ellam, Rich EIlam & Hugh Brewer."

In the late 17th century there was a fervour for philosophical and scientific discussion . Those with Masonic knowledge in common,  would   arrange to meet privately to discuss Freemasonry; and what they had learned when they first became a Mason. The mythical history would get embellished, providing the respectability of antiquity; and the moral code would be embroidered by reference to biblical exhortations because the Bible was regarded as the ultimate and definitive authority in moral matters.

So why did they seek admission to groups  with whom they seem to have had so little in common and unlikely to have been attracted by the possibility of acquiring mystical knowledge.

         It leaves the means of recognition as the only other knowledge acquired at the ceremony. There are the dangers of travel and the turmoil of the times evidenced in  the fact that Ashmole became a Mason  before starting on what might be a hazardous journey. From a quotation from Travel in England by Thomas Burke. Of Stuart times he says "The dangers of travel were so much recognised that any man going on a journey could, on a request to the vicar of his parish, have prayers offered for his safety."  In 17th century England, where political and religious factors as well as outright villainy could spell danger,  anything which guaranteed a safe lodging  would be a great boon. That was what the operative Masons could offer to those possessing the Masonic recognition secrets. A  wish would develop to have the independence of one's own Lodge with  one's own friends, and perhaps even to boast of secret knowledge.  Freemasonry  would be an almost inevitable consequence.