Extra hassle is manageable. Sites or programs that want you to put in a birthday are extra hassle but objectively better than something like submitting an ID. Privacy degradation is also manageable as well. It just depends on the solution.

We've had decades of age gating being "are you 18+ or not" yet it is only now that talks of something more enforceable are coming up. This discussion is largely about how one can create a sense of safety and protection. For the more extreme end it's face scans and submitting ID. Even though these are bypassed by any teenager who cares they are still being pushed seriously because it instills that sense of safety and protection for children. Security theater is just a part of managing the internet and not going away unfortunately.