I know something about drugs. There are "weak" drugs, like weed or alcohol, and there are "dangerous" drugs. Some dangerous drugs are common like the cocaine, and some others are more weird like heroine and new ones like crocodil; the weird ones usually are hard to produce. Some drugs are "useful", for example the caffeine or nicotine, and some are harmful like the meths; in this last category there are many illegal ones. Both, the "harmful" and "functional" drugs are sometimes equally addictive; also for old civilizations "dangerous" drugs where very important, so if it is functional or not depend of the society.
Of the legal drugs in Chile the nicotine, the alcohol, and the caffeine are legal. The first two nevertheless are controlled by the state, so you can´t sell it to minors and have more taxes.
Marijuana in Chile its relatively highly consumed. It´s illegal to sell it and produce it, but it´s not illegal to consume it. Marijuana shouldn´t be illegal because it´s not harmful. I don´t believe that consume it leads to experiment whit other drugs, because for the people who consume it is know that other drugs could be dangerous.
I believe that if drugs where legal there would be less organized crime. The problem of the crime it´s not about drug, its more about poverty; you can see this because rich people also consume hard drugs and don´t commit this crimes.