I don't think substance abuse can calm anyone’s mind all the time. It is a very temporary thing. Only tamasic people does it. Substance can give you a high for some time, but after a while if the substance is not available, you become aggressive and may go out of control. You will become a slave to your monkey mind and will send up doing all the nasty things. It will become an addiction and will make you go down in life. They choose this because of sheer ignorance and addiction.
Meditation is not like that. It needs certain discipline and benefits are huge. Even after the meditation, you can still feel the benefits of calmness and awareness. As your practice progress, you will see a host of benefits physically, psychologically and spiritually. You will become a better person each day and will be a blessing to the society.
Substance abuse is not only illegal, but is an evil and a peril while meditation is a boon and brings in lots of positive changes from inside out.back