If ads were merely about being informative, they would be boring. But ads want to manipulate, so they have to be flashy and appeal to your emotions.
They pollute your mental headspace, and have no place in a healthy society.
Let's ban billboards. And then let's follow that up with a general purpose ban on paid advertisement.
Legally speaking, the validity of banning billboards tends to be evaluated based on the Central Hudson test. More practically, there's numerous limitations to commercial speech... for example, you can't blare an audio ad from your rooftop.