What is the point of automatically removing child porn so it's not searchable.
Well, if it works to prevent people from seeing it unintentionally then it means the Google search engine provides more relevant search results. So that's a major improvement in Google's search engine.
If it's automatically identified removed, then presumably Google would be able to purge ephemeral copies from their caches and whatnot, which is probably nice from a liability perspective.
It might help to reduce casual interest in the subject if it's not easily searchable.
It doubt it would prevent anyone actively trying to find it, and it certainly won't stop the kinds of people who would go to the length of producing it; at least, I can't imagine that fame through improved search engine results is a significant part of their motivation.
The question is what is the impact on the people who might make a transition from casual interest (if they could view it by searching) to actual production? If it helps prevents that, it's a win. On the other hand, if these people deal with frustrated urges by just going ahead and making their own, we'd have to call it a major failure.
Ideally, someone has actually done the research and determined that yes, blocking casual searches for child porn should amount to a net benefit.
In practice it wouldn't surprise me if it's a move to reduce the threat from Attorney General's who see child porn in Google's search results as an easy PR and courtroom win.