The fact that some (bad) programmers already blindly copy SO code does not detract from the original argument that Copilot is dangerous because it effectively copy-pastes SO code blindly.
a) I'm familiar enough with the code/topic that I'm able to judge whether the suggestion is good, or
b) I'm not able to judge, and need to consult other sources.
In case a, I could have just written the code myself. In case b, I still need to read up, so the potential gain is that Copilot gave me a hint as to what I should search for. But even that hint can't be trusted - there was another comment where Copilot suggested to use MySQLi in PHP, which has been the wrong choice for a long time.
So if the suggestions need scrutinization, the target group I see is people who need to write a lot of code in a familiar area, and are limited by the speed at which they type. This is arguably a very small set of people, and is unlikely to be the main user group of this tool.