Attract Mode only really works if the story line of the game isn’t critical. There’s no garuntee a given arcade goer would even see it, either out of impatience, or because they slot their quarter immediately after someone else leaves the machine, leaving no time for attract mode to engage.
Everything one really needs to know about the game, one needs to be able to get from what one sees during actual play. What does one need to know about Ryu? It shouldn’t be more than what one can see by watching Ryu fight.