HubSpot is in the initial states of the video product but there are ways to make some of it work while they get it everywhere fully integrated.
If you are using HubSpot Video, then you are using the Vidyard GoVideo chrome extension, so if you want to include videos you've recorded from there, you can always click on the copy link and thumbnail button and then paste on the email you are creating on the marketing side.
I know this does not include your "HubSpot Video" files that you are hosting through the file manager, but it is something. You can also download the videos from HubSpot into Vidyard and then use them from there.
Hope this helps. If it does, please mark this response as a solution.