It has become a big business: Addiction Treatment With a Dark Side - In Demand in Clinics and on the Street, ‘Bupe’ Can Be a Savior or a Menace
It's an opiate agonist/antagonist. Apparently it's a mild high. I know a doc who prescribes it. He is all about $.
My bias tends to be in favor of sobriety and standing up and facing life and oneself directly, but those things are difficult for everybody. In the UK, however, certified addicts can pick up their heroin etc at the docs' office on the way to work. The NHS figures it's cheaper than rehab. Of course, the NHS also considers death cheaper than cancer treatments.