There are several reasons why someone might choose to use more than one light switch to control the same lights instead of using a single switch:
Convenience: Placing multiple switches in different locations allows you to control the lights from various points within a room or area. This can be especially useful in large rooms, hallways, or staircases where having a single switch may require you to walk a considerable distance to turn the lights on or off.
Accessibility: Having multiple switches at different heights or locations can make it easier for people with mobility issues or disabilities to control the lights. For example, a person in a wheelchair may find it more convenient to use a switch located at a lower height.
Multiple entry points: In some cases, a room or area may have multiple entry points, such as a bedroom with doors on opposite sides. Placing a switch near each entry point allows you to conveniently control the lights when entering or exiting the room from either side.
Circuit design: Electrically, using multiple switches to control the same lights can be part of a circuit design that allows for more complex lighting setups. For example, you might have a three-way or four-way switch configuration that enables control from multiple locations using specific wiring schemes.
Redundancy: In certain situations, having redundant switches can be helpful. If one switch malfunctions or needs repair, you can still control the lights using the other switch(es) while the faulty one is being fixed or replaced.
Energy efficiency: By providing multiple switches, you have the option to turn off the lights from any location, which can help save energy by preventing unnecessary lighting in unoccupied areas of a room.
Ultimately, the decision to use multiple light switches depends on factors such as convenience, accessibility, circuit design, and personal preferences. It offers flexibility and control over lighting, accommodating different needs and situations.