Age verification doesn’t work

It is not like kids/teenager who currently visit the big porn sites like pornhub will say: "Oh I can't, let's read a book instead"

They'll just get it somewhere else, private chatrooms, torrents, etc and from probably even less regulated and more nefarious sources that also serve stuff super hardcore or completely illegal.

But it will be harder for them, the same way it's harder to get alcohol if you don't have a proper ID, and just that will prevent a good number of them of accessing it or at least accessing it in a regular way.