I would find it handy to be able to replace media in the bin by dragging a file in the bin, holding ALT and dropping it over another clip in the bin. This way I can consolidate my files in the bin. Here's an example: I have a low res gettyimages file in the bin, I import a high res file into the bin using the gettyimages extension (not importing into windows where you can do a "replace file"), I should be able to click and drag with ALT held, to overwrite the low res clip with the high res clip and the changes are reflected on the timeline. Another use would be if you have multiple versions of the same file, duplicates or obsolete media that you want to consolidate down to a single file version. You can do this with media from bin to timeline by holding ALT and dragging over another media, so would be the same functionality by within the bin. Holding CRTL duplicates a clip.