just to add to what hborre has said about mesh lights: Area lights ARE mesh lights in that they work exactly the same. When Poser 11 first came out I did a bunch of tests with area lights and square mesh lights of the same size. exact same lighting results in the render from either. They are interchangeable when you are using a square. The advantage of area lights is they show up in your lights list but mesh lights can be any object you want to emit light. I sometimes use light fixtures in room props as light sources or use a torus as a ring light attached to a camera.

Here is a bathroom prop that I turned the light fixtures into mesh lights to get a more real lighting.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740