Yeah, you're right, you just literally never see any transaction using the 0.01 unit (fen) and only very rarely see any transaction use the 0.1 unit (jiao).

Isnt 0.1 one mao?

That's another name for it, yes. Similarly, yuan is sometimes colloquially called kuai. Sort of like dollars vs bucks.

Japan has sen (銭) as well, the coins were just inflated into oblivion years ago. Still used for eg stock prices though.

Oh interesting. In China it is still used (you can still see prices with decimals beyond share prices and petrol stations) though on the way out.