Mafukasa is an interesting situation where I think it's a good comparison to make. But that everyone makes the comparisons wrong. Tsukasa is not secretly empty like Mafuyu, the contrast between them is interesting because of how full Tsukasa is.
They're both Sekai holders which is inherently interesting and draws parallels between them. He's yellow she's purple so they're opposites. I think that's really fun.
But the way everyone writes them is annoying as fuck. Also they don't interact so there's nothing to talk about yet. And that's fine. There doesn't need to be connections between every character. But wouldn't it be fun if there was