Right, the thing it reminds me of is the long-term impact of reading to your kids at a young age, it has measurable effects equivalent to expensive professional education choices you could make later on in life, although I forget the exact comparison.

But also it doesn't have to exactly reproduce the harms of smoking. It could be that the effects are primarily present tense and completely gone if you stop the habit, and nevertheless, amount to a cumulative social harm that makes it a worthy analogy to smoking. Social media also doesn't cause secondhand smoke or stained teeth, or unpleasurable odors on your person or home or furniture. It doesn't leave butts or debris on the ground. There's probably a lot more I'm not thinking of either, but you can see how nitpicky that starts to feel.