I think the thrill of finding a rare v1 charm drop would be severely diminished if they weren't no trade. There are few things more exciting than stumbling upon a rare drop.
I'm pretty confident that Hunter's intent is to make people spend dozens of hours in ldon to prove their dedication.
If they were made droppable, then people could spend dozens of hours farming the plat to buy the charms off others. The more avenues to a reward, the better imo.