I think it would be of great benefit to have a feature where you can select specific files to upload to the file column on specific status changes. Or all types of column changes to allow you to upload files without actually manually selecting them 
Hey,
You can use an external automation tool, like Integromat, to action this as long as the file has a public URL.
Use a webhook in Monday upon status change to trigger the Integromat scenario which would then grab the file and upload it to the file column on Monday.