Xiaomi doesn't really make air filters and vacuums, they are made by their partners. Xiaomi is providing retail service to those partners. Xiaomi also provides partners other services, like pooling purchases to lower price and pooling loans to lower rate.

One financial analysis of Xiaomi I read (it's in Korean, I couldn't find anything in English) is that it is in part a lending company funded by float from manufacturing partners. Xiaomi has a personal loan product which grew by 100x in two years to ~1 billion. Liquidity comes from delay between retail sale to partner payment.

To begin with, money in China are super duper cheap to begin with. I guess, even "super duper cheap" was not enough for Xiaomi

Isn't interest rate much higher in China compared to US?

Nominally, yes... the "street rates" are completely random, and if you manage to qualify for any government endorsement, state banks will be ready to bamboozle any amount money on you.

> useful non "tech" things like escooters, air filters, vaccuums.

Since when scooters, air filters, and vacuums turned "not a tech?"

before some starup in Silicon Valley started related business

I cant imagine xiaomis finances being balloon. I think it currently sits at 28b$ and makes it super cheap. Same goes with jd.