To expand on your #3, it also gives parents a way to have different policies on different devices for the same child. Perhaps absolutely no social media on their phone (which is always drawing them, and can be used in private when they're supposed to be doing something else), but allowing it on a desktop computer in an observable area (ie accountability).
The way the proposed legislation is made, once companies have cleared the hurdle of what the law requires, parents are then left up to the mercy of whatever the companies deem appropriate for their kids. Which isn't terribly surprising for regulatory capture legislation! But since it's branded with protecting kids and helping parents, we need to be shouting about all the ways it actually undermines those goals.