Antenna gain and directionality are always inversely proportional. Even so called omnidirectional antennas are directional in that they do not radiate the same in the vertical plane Vs horizontal plane or visa versa depending on it's mounting orientation, thus trading gain for directionality like any other antenna.
The higher the gain the more directional the coverage, it's a physical law thing. There is one free lunch advantage to gain antennas in that the gain is seen in both it's receive and transmit functions. It's like adding more transmitter power and receiver sensitivity at the same time.