there's not even a way to play scd video AT ALL other than on an emu or segacd. nearly all games/all developers use their own format and their own player to play the videos. it's very unlikely someone would sit down and try to figure them all out to make a player.
My guess is that *if* someone does sit down and figure *one* out, it'll be for something like one of the Lunars, or Snatcher. Then people will feel compelled to test it with every game they can get their hands on, particularly those by the same developer. It might even work on one or two other games. But really, there are only a few games that anyone would be interested in the video for, unless people have a fmv fetish, or something.
Games like Snatcher and Lunar have no "real" FMV, this is no digitized video like in Double Switch, Night Trap or similar titles. It's more a real time animation similar to the GIF format. The video data for this kind of FMV is very small (the Lunar ISO is only ~30 MB and the files on the disk are only ~10MB). The biggest part is the audio, either compressed (Lunar 2, Popful Mail) or CDDA (Lunar 1) or both (Snatcher, Vay).