i'm still a noob here but our current situation kind of looks like a buildup of buying pressure at the trend line. as if it's about to explode. maybe?
You can't always go by the order book.
It takes minutes for bitcoins to be deposited to exchanges. Fiat deposits take days.
People with fiat on exchanges tend to place bids rather than just leaving it dormant in their accounts.
Those with coins will usually leave them in paper wallets until they're almost ready to trade.
Also, BFX gives you the option of hiding your order and I can't see any game-theory reason why you WOULDN'T.