Essentially the cards get less exposed as time goes on to replicate increasing risk, matching what Shou and Kasen both had to go through to make progress in their relationships; that's why the final section is just risk (aside from seeing the first card): that's how standard BlackJack is played. Rhythm you play on the bottom as Shou following Raiko's lead. IcedLemon actually pushed for more obvious explanations of stuff like this (mainly the card game explaining the risk super blatantly), but I wanted it to be implied, with the 10 then the jack following after helping to get the point across.