Now, any appearance of cannabis is abuse. Any use of it is criminal. Tobacco, as in your example, may be discouraged using overpricing and demonization, but its use is legal, and no criminal charges can be levied against those who use it.
The restraints against tobacco are nothing to the current restraints against cannabis. So, making cannabis legal, and placing an extrordinately high tax on it (which causes smuggling-but a high tax doesn't have to be placed on it) could cause some degree of criminal activity, the criminal activity doesn't approach that of it being illegal, and is therefore would be less if it is legalized.