Doesn't affect light but does affect sharpness. The following quote from this article explains why:

“The Bayer filter itself does NOT make the image less sharp. The Bayer filter is simply a way to designate a color filtration for each individual pixel. If the image were rendered without the interpolation of this color information, it would be just as sharp as a camera/sensor without this filter. However in that case you would not have accurate colors. So it is technically the interpolation of what the Bayer filter captures, creating the final colors, which makes the image appear “less sharp”.

And don't forget this camera uses a 40MP sensor. Note that many other high pixel camera's also have alternative filter setups because of sharpness and moire issues. Think of the Nikon D800 without AA filter.

Plus other solutions for color sensors exist that try to work around that sharpness loss, think of FujiFilms X-Trans sensor config. Also a good read on this topic.

So far for the filters that is. Because there are other benefits to a monochrome only solution. It's like having a camera where you can drop all the features, menu settings, processing power, filters (see above) etc that are only needed for color processing. And then use these for improving the B&W image from a 40MP raw image capture.

I don't have details on that but it makes sense that if you only need to make B&W images work within a similar product and budget (a way higher sales margin but less sales) that you can improve upon that and excel at it.