By definition addiction involves pursuing substances or engaging in behavior repeatedly despite negative consequences in one’s life.

Any behavior or substance that causes serious addiction is still bad regardless of whether it causes death or other negative health effects. The addiction itself inherently causes suffering because the addict is engaging in something despite the negative consequences in the rest of their lives. The negative consequences cause suffering and the psychological pain of wanting to stop and not being able to stop also causes suffering.

I know some other commenters mentioned caffeine addiction but nicotine and opioids (and also behavioral addictions like gambling) are vastly more addictive than caffeine.

Negative consequences from addiction can involve more than loss of money (although loss of money is still a significant thing of course.) They can cause damage to one’s career, family relationships, friend relationships and so on. Even if the addictive behavior or substance has no other inherent negative health effects.

In high school I had a really bright and motivated friend. He went to an Ivy League school. He became horribly addicted to World of Warcraft as a freshman. He spent so much time playing the game that he damaged his grades and GPA. He almost failed out of school. He had to make serious effort to stay in school. And he had to spend tremendous mental effort to avoid playing additive games anymore. That’s just one example.