Not necessarily. Addictiveness is not directly related to potency.

From what I’ve heard, most addicts prefer heroin to fentanyl, even though it’s less potent on a weight basis.

They prefer heroin likely due to the fear of overdose. I pushed the button as often as the Dilaudid dispenser would let me after surgery. It's a pretty magical warm blanket. I understood the appeal immediately. All your worries melt away, and you're floating in a cloud.

Heroin produces a stronger euphoric effect than synthetic and semi-synthetic opioids like Dilaudid and fentanyl relative to its less desirable effects like respiratory suppression. Studies have shown that recreational opioid users prefer heroin to other opioids for this reason.