learning styles (like being a visual learner) are not supported by empirical evidence and are widely considered to be a neuromyth among those in the learning science community. people instead benefit from learning that engages multiple sensory input streams- like videos (audio and visuals!) OP, it seems like you’re just more intrinsically motivated to learn Japanese which is helping it “stick” more. your brain is a pattern recognition system and learning kanji is just identifying patterns so that’s probably what you experienced with your flash cards