There is some logic in the conversion as it helps show scale - if you run a lemonade stand it may be true to say you can invest $10 and profit $20, but not true that you could invest $1m and profit $2m, whereas in a car manufacturing business you might be able to invest $Xm and profit $2Xm, but investing $10 is unlikely to give you any return. These two scenarios can't both be explained as "you can invest 1 and get 2 back".

That said, a single quote, even with conversion, doesn't help much here - if a reader wanted to start a farm now it doesn't give them any idea of whether 20 yuan is the minimum or the maximum investment (I presume it's below the minimum anyway).