What's the downside to the ban as described, when compared to the status quo?

If there's no profile already, then they can serve the ad, since it's not a profiling-based ad and they don't need to know if the viewer is a minor.

If there is a profile then they have the knowledge to avoid advertising based on that if it's a minor.

I don't see why ID verification needs to come into play?

I would love to see a ban on _all_ profiling-based ads, but this seems like a step in the right direction to me.