Given that certain CMS instances have only video media uploaded to the library creates an issue with creating simple layouts at-a-glance. This causes some frustration but allowing the ability to upload or attach your own screenshot as a thumbnail for the video media may alleviate this.
When perusing through one of my client’s media library I found that they have 10+ pages of only video media. Currently, I have been downloading the individual video files from the library and opening them to view what each is. They are utilizing tags and have renamed some files in the library, but if there was an option to upload your own screenshot to individual media in the row menu, I’m sure this would help a circumstance such as this as I could then take screenshots of each video and upload them so that the customer and I could quickly select media even when creating layouts.