Works well 4.9.6

I’ve read of some people having issues with this for larger files but I haven’t encountered any issues yet and have dealt with fairly large PDFs and images. Maybe it’s your server configuration that’s causing issues.

Can download attachments on a per post/page basis (via meta box in sidebar) or site wide (Media > Import Attachments from the menu).

It’s great how it stands out in the editor sidebar so it’s obvious the post you’re looking at has external content. If there is no external content then the panel isn’t visible.