I agree with the cigarette analogy up to a point, but the UX consequences are easy to understate.

A lot of what makes these products feel “good” in the moment is exactly what regulators may end up targeting: no stopping points, instant continuation, algorithmic relevance, autoplay, low-friction notifications. If you remove or weaken those things, many users will probably experience the result as worse UX, even if the policy goal is reasonable.

So the hard part is not just “ban addictive design”. It is deciding which kinds of friction are legitimate product safety, and which ones become the digital equivalent of cookie banners: technically protective, but broadly annoying, ignored, and eventually hostile to normal use.

Starting with kids makes sense politically and morally. But if the regulatory logic is “this is bad for everyone, not jus minors”, then adult UX probably will get pulled into it too.