1) You use a mobile phone with, 20ms? latency 2) The price displayed to you is 20ms late 3) You accept order at this price 4) The actual price might be less,

1) You use a mobile phone with, 20ms? latency 2) The price displayed to you is 20ms late 3) You accept order at this price 4) The actual price might be less, so a firm can buy it and sell it slightly higher. 5) You get a fill at a better price than you thought. - There is a premium to Robin Hood vs other apps because most users are on mobile, where latency is likely to be higher.