Lol, Kaido is a fish. Well, I was wrong about him not having a devil fruit, but this does connect back to the beginning of Wano where we saw Koi fish trying their hand at climbing the waterfall entrance of Wano. Kaido, symbolically, made it to the top and became a dragon. Speaking of, I wonder if this is the reason we didn't see Kaido enter the country.
But being a fish does tie Kaido quite well to Ebisu town thematically. Ebisu is named after the god of fishermen and good luck. Yasu, a resident of Ebisu, "the fishermen" expressed the importance of catching that blasted fish, Kaido. Maybe some lucky fishermen can nab the game?
And finally, I've been wanting for the Robin, Neko subplot to come into play. I thought it would wait until Teach came into the main picture, but Linlin mentioning her specifically means Robin might have some role to play at the top of Onigashima. So even if she fights Maria, she can still make her way up.