I think there needs to be a distinction between physical addiction and psychological addiction. For example, if you're addicted to cocaine, that is a physical addiction which will give your body a "withdrawal effect". It is very real and may harm your body severly.

On the other hand, psychological addiction is not a real addiction as it doesn't harm your body directly. Good examples for this are playing video games, being on your phone a lot, or being on Steemit all day. It is basically the same as spending much time on any other hobby.

Of course, as @javalord points out, spending too much time alone can take your attention away and put you in isolation, but that is not an inherent feature of being on Steemit. It is rather a consequence of spending time inside your house, for instance. In comparison, consuming drugs will harm your body and wants you to consume more in order to feel better.