Feels like maybe you're just noticing this because it defaults to Chinese. Is that true?

How many sites do this but you don't notice because they default to English?

This is really strange, but the link provided has an iframe pointing to https://mimo.xiaomi.com/coder

When you look at the source, you can set it to English from the params https://mimo.xiaomi.com/coder?lang=en but there's a small bug, the hero subtitle isn't translated but everything else is.

Wondering why this is in an iframe.... so strange

Language support was probably an afterthought since their target audience all read Chinese