A: Yes, for two important reasons:
- Directional WiFi antennas focus signal transmission and reception where the signal is needed most. For example, an access point (AP) in the corner of a building should have an antenna that's tuned to work in a 90-degree arc. That design provides the best signal strength to clients while avoiding transmission outside the building.
- Attackers have more difficulty monitoring WiFi from outside the building if the antennas point the signal inside. Directional signals won't stop a dedicated attacker, but they'll certainly make attacks more difficult.
When you plan your WiFi network, either avoid placing APs at the building perimeter or use directional antennas.