Pfft well, I guess they'd get competitive over it for a while. But might move onto something else quickly if it doesn't get them going enough. But they'd probably try at it enough. Could the plot of Free work replacing swimming with karuta? "The cards are alive."

Which reminds me I saw some art snowboard Haru and "the snow is alive" as he wobbles across it.

Memorization games... they can be tricky.