SMART is a very general term. It can add liquidity only, find liquidity, hit dark pools and/or ECNs, go to a MM that will reduce your cost etc. All that does not mean it is using some advanced logic to do what is best for that order at that time based on the size of your order and the current market place. It requires YOU to be SMART enough to choose how to execute your order in that market with your expectations of price movement.