It’s really the same addiction. Instead of shooting up to get high they get just enough to keep from getting sick without being high and possibly overdosing. It might help some, but I bet a lot of addicts would still do heroin for the high. On the whole though I think it’s better to treat addiction as a medical problem rather than a criminal one. I’m speaking as someone who lost people near and dear to me to heroin addiction.
As the daughter of two meth-heads you have my sincere sympathies.