One of the arguments put forward by some members is that having CSAM on one's phone will not stop child poronography. What these people fail to understand in my opinion is that if CSAM catches some people, some of those caught will have a history of looking at such illegal images which means the police will be able to investigate that history. Things like where else did the person go to look at images, names of people who helped with the images. You catch the small players to get to the big players and I feel that is what will happen with CSAM. Those who are caught will eventually lead the police to the big players who are creating the material.
The police has the same principle with the drugs trade, go after the dealers to get to the creators of the drugs. Remove the creators, you remove the problem. Same with child porn, go after the watchers to get to the creators. Remove the creators you remove the problem.