Opioid addicts use it to "get by" when they can't their drug of choice. It is also used to "boost" the high by combining it with other opioids.
It gives you the same euphoria as taking an opioid. In my opinion anything that gets you high is not a legit treatment for opioid dependence.
What worked for me when I finally kicked opioids a few years ago was to taper off using suboxone quickly over about 2 weeks to get past opioid withdrawal, and then over about a year you have to train your brain to be high on life instead of substances. Easier said than done, the 27th try was a charm. Clean for 2.5 yrs now.