Videos are used in a wide variety of ways in games. Like the next video on Texas hold'm poker.
Visuals may be appealing and may look flashing but will it get the desired teaching result. Card games are for example mostly learned in a real-life setting with all cards laid open, which get you playing really fast. A non-life game example may be an interactive tutorial game against NPC's (non-player characters).
The point I'm trying to make is that the choice of media-mix in games should depend on the desired result. Research comparing newspapers and tv news have shown that the retention rate of newspapers is significantly higher. Therefore video's should never be used to transfer dense amounts of information.
It can of course be used to inspire awe and add drama. Or even to clarify a spatial orientation of characters in a game-world. But refrain from transferring to much information with animations or video's.