I think it’s just to indicate that you pause a bit while reading it.
seems like its breaking up the sentence to help with readability. the を is acting on ごみ but what is directly following the comma isnt the action いれた. its the added information of ごみばこじゃなくて ちがうはこに. so that comma is helping to delineate object from the rest of the sentence.
2 comments
I think it’s just to indicate that you pause a bit while reading it.
seems like its breaking up the sentence to help with readability. the を is acting on ごみ but what is directly following the comma isnt the action いれた. its the added information of ごみばこじゃなくて ちがうはこに. so that comma is helping to delineate object from the rest of the sentence.