There are two reasons behind 404 being a bad response code to use for empty results.
- Did I get a 404 on this endpoint because the endpoint doesn't exist? Or did I get that because the object I was looking for doesn't exist? Great, I need to dig into the response body to find out, indicate that I can either get a 200 or a 404 with this endpoint, and deal with the odd case where the API returns HTML regardless of the MIME type in the Accept header if the endpoint itself is not there because "fuck you, couldn't be bothered".
- Some HTTP libraries will consider anything that's not a 1/2/3xx an error. That can be annoying to deal with.
If anything that's not 1/2/3xx is a problem then 410 won't be a solution. And I doubt that your http library having issues to handle 4xx can handle 1xx correctly.
- Did I get a 404 on this endpoint because the endpoint doesn't exist? Or did I get that because the object I was looking for doesn't exist? Great, I need to dig into the response body to find out, indicate that I can either get a 200 or a 404 with this endpoint, and deal with the odd case where the API returns HTML regardless of the MIME type in the Accept header if the endpoint itself is not there because "fuck you, couldn't be bothered".
- Some HTTP libraries will consider anything that's not a 1/2/3xx an error. That can be annoying to deal with.