@cjd making pornography more difficult to access is a damn good start. making folks get out the credit card or cryptocurrency to buy a VPN service is a significant barrier to kids randomly stumbling upon some seriously fucked up porn on ordinary, popular web sites as well as teens being able to access it conveniently and secretly.
while there will probably always be small groups of the most dedicated coomers sharing porn with one another, loads of folks pay for streaming services cause they're too lazy and technically inept to use a torrent client, the same effect would happen with porn.

it's more effective to target the producers and distributors than have a bunch of secret police going 1984 on the consumers. seize the domains and servers of the largest dedicated pornography distributors on day one, give social media sites a chance to have the jannies clean the place up and remove the newly illegal material and ISPs a chance to work out the technical details of blocking foreign porn sites.