The USD value reported by the steemit web pages are not based on current market value: it is a multi-day averaged value. In volatile cryptomarkets, the value that is reported is nearly useless, and I've suggested before they should report a more accurate value. To get a more accurate reading, you would be better off using the prices on coinmarketcap.com. You will find our rates are much better than what you thought based on the prices reported from steemit web site.