They're not just gateway drugs, but also a huge problem in and of themselves. I have a friend who went to rehab for heroin and he said most of the people there were addicted to oxycodone, not heroin. Opiates are not to be trifled with, yet some doctors are more than willing to throw them at people. My other friend was prescribed Norco for a sore throat >:(
I recently burned my hands with bacon grease while cooking which was a painful experience and was prescribed Norco. The pain was pretty much gone in the morning ~12 hours later and I had only taken one dose (which made me feel terrible, btw) and didn't take any more. I imagine many people just take the dosage until the prescription is gone.
Suboxone helped me kick a 6 year heroin addiction. For an actual addict, there is effectively no high from it (aside from the relief of getting rid of withdrawal symptoms, which is very different from an actual high). So, you can dismiss it as much as you like, but it (coupled with excellent support from the government-run clinic) saved my life.