Is it about automatically opening the gate when you appear near it? Almost all smartphones now have the option of enabling BLE broadcasting. This works in the background and does not drain the battery faster. The receiver at the gate detects the presence of such a smartphone at a certain distance, establishes a connection with it and performs authorization. If it succeeded, the gate is opened. The whole operation takes a split second. Of course, the automatic mode can be switched to manual.
The gates do not have bluetooth, the gates are controlled by radio, so how will your phone connect to the controller? unless you have infrared control, then any remote control application from the store that has the function of copying the original remote control.
Have you thought about the simplicity of control and safety? In addition, not every control has a separate open input.
Virtually every driver has so-called multi-family building mode. In this mode, the gate probably always opens when you press the button on the remote control. Closing is automatic. In more sophisticated solutions, the receiver has two outputs with opposite states. One contact opens the gate in a classic way and the other breaks the photocell circuit to prevent it from closing. It's a case of someone stopping in front of the gate for a long time.
Where security reasons do not allow automatic opening, this can always be done at the push of a button in the application. I live in a multi-family building. I can open the gate by means of an intercom. This solution is widely used in many places. I think the potential threats are similar to those of automatic opening.