1. technically, pure black and white don't need to go through that node because they are the same in all variations of a certain space. However, the moment you go beyond pure black and white, the gamma correction node is necessary. For example, in sRGB the 50% gray is not equal to Linear 50% grey, rather it is equal to…
and also, if the purpose of setting normal maps for example in a linear color space is only in order to avoid the color correction made by maya, would it be ok to set it as any other color space?