Addiction is sometimes described as something that is done repeatedly and is harmful. I can't get by without breathing, so I need to do that pretty often, but as it's not harmful, it's not an addiction.
The answer to your question is it depends... I don't think there is anything wrong with playing a dopamine hitting game on a 10 minute bus ride home from work (it's no different than the buzz from a shot of espresso), but if you are spending so much time that you are harming yourself (physically or emotionally) then that's an addiction.
There was a talk posted a few days ago here by Dr Gabor Mate about addiction:
Listening to music is essentially a drug in that it releases pleasurable neurotransmitters. I think we need to understand the positive and negative impacts to ourselves like you suggested.
I think it's both. People seek an escape and phone apps are extremely addicting.