I honestly never questioned the crests everyone was assigned to in Adventure as a youth but after growing up and recently rewatching the series again, I have to say that I think I found all of the attributes to be powerful and true except Yolei and Cody. That is I agree with Sincerity for Yolei and Reliability for Cody and I think Davis works well with the crests of Courage and Friendship and proves so, but Yolei and Cody just show up in the Digital World and are handed Digimentals and I never agreed they were good fits.
Of course, I like Digmon and Halsemon just fine but the problem is that while Cody is certainly smart and Yolei has a good heart, it just seems like the opposite would have been a better fit if they’d had a chance to prove themselves because Yolei was always so intelligent and proved so many times over while working with Izzy (whereas Cody was just like, “Yo I’m a genius. Peace.” and hardly helped with all the D3 research and such) and Cody was such a strong kid with a strong heart and he was caring and compassionate and it really showed throughout the series, especially in the final arc when he talked about his dad and when he cared enough to go back for Oikawa to rescue him because he didn’t want him to die, no matter what he had done in the past. It’s not that I don’t like the characters, I just think their crests were mixed up.
Of course, my own theory is that they just wanted to associate a boy with the “boy’s crest” (Joe and Izzy) and a girl with “girls crest” (Mimi and Sora) but that makes me sad that they would go to such lengths to separate the crests with gender distinctions that reinforce stereotypical notions within the gender binary.