There's a gradual shading from "soft paternalist" solutions to bans. Making someone take an extra 5 seconds to get their choice would probably not be considered a ban by many people. What about a minute? An hour? A week? What if it takes an hour, and you're a poor person who can't afford to get child care for the hour, or pay the taxi fare to go to the banned store on the outskirts of town? What if buying and having the item increases your chance of being harassed by the police, without the item itself being a crime to buy or have? (This actually happens in some places with open carry of guns.) Or increases the chance of child services coming and requiring you to go through months of hearings to get your children back?

Also, "soft paternalist" solutions tend to slip. If you want to discourage people from doing something and forcing them to go out of their way to do it doesn't discourage them enough to satisfy you, it's very tempting and usually very politically feasible to say "well, that's not working, so we need stronger measures like a real ban".