The biggest problem is that they waste your time even when the content is ostensibly helpful, since the search result is usually listed after the Stack Overflow

The biggest problem is that they waste your time even when the content is ostensibly helpful, since the search result is usually listed after the Stack Overflow page it crawled from anyway. Each click steals a few seconds of developers’ time, which adds up, given how frequently these types of results pop up on Google search lately. That makes them worse than useless, they actively subtract value.