Slidebank handles video files (within file size limits) as well as PowerPoint, PDF, Word, Excel and other types of file.
However, the context in which these video clips will and will not play within the Slidebank tool itself varies.
In short:
Video files will play in Slidebank; video embedded in slides will not.
In Slidebank, what you see as slides are actually just images of the slides that are stored on the server. This is true for the thumbnails you see in the slide sorter as well as the slides you see in slideshow mode. Since these are just images of the slides, the video won't play in Slidebank if it is embedded in the slide itself (though will play on download to PowerPoint).
However, video WILL play in Slidebank if it's a video file that has been uploaded to Slidebank (not a clip that's embedded in a PowerPoint file). If the video clip is added to a slide selection within Slidebank or saved into a Virtual file, it will play in the viewer.
All types of video (video clips added in Slidebank or already embedded in slides) will play when the file is downloaded to PowerPoint.