Incidentally, the bill doesn't even say they can't use them; it just says the platform has to tone down the Skinner box part for children.
> This subdivision does not prohibit a covered platform from permitting a user who is under 16 years of age to create or maintain an account on the covered platform if that user is not provided with any addictive feature.
So it's not a social media ban. It's an addictive features for children ban. And it seems kind of obvious that running an optimization algorithm with engagement/attention as the objective is going to be bad? If that optimization works, you would almost necessarily have to be detracting from other parts of the person's life (interfering with study, exercise, socialization, etc.), which seems to be exactly what we see in aggregate (lowering test scores, increased isolation, etc.).