Because they don't want you to do normal math and realize how much you are being ripped off...
Also, we are giving users more than market value on products and selling brand new products under retail. The same products would be more expensive if you were to buy them directly from the store.
Converting $1 = 10H might seem like a simple conversion, but you'd be surprised how difficult it can actually be for many general consumers. I've seen people bring out calculators to split a $130 bill evenly between 13 people.
We're testing to see what works and what doesn't right now. If you think about it, people are more likely to buy or sell if the number is higher. But we will only know if people get used to it within a matter of days.