When we create our scenes in Unity, we have three options for lighting. We can use real-time dynamic light, the baked lighting approach, or a mixture of real-time and baked. Our games perform more efficiently with baked lighting compared to real-time dynamic lighting, so if performance is a concern, try using baked lighting where you can.
Area lights are distinct from the other types of light in that they can only be baked. This means that real-time rendering will not take place during gameplay. The reason for this is to conduct all the processing regarding area lights prior to gameplay. This processing, if accomplished in a game in real time, would likely result in sufficient lag.
