I agree that the parent comment is overly worried by issues that are well-known if you program with IEEE arithmetic. But, about your second paragraph, I disagr

I agree that the parent comment is overly worried by issues that are well-known if you program with IEEE arithmetic. But, about your second paragraph, I disagree. It turns out NaNs are quite useful to hold un-determined values, unknown values, error values, etc. The NaN will propagate through intermediate operations and "contaminate" the result in the appropriate way. If you use this property of NaNs, you can exploit IEEE conformance to do a lot of hard work for free. This is used in image processing all the time. You have an image; it is projected onto a grid; some values were not sampled and are unknown. Fill them with NaNs. Then run whatever operations you wish on the image (scaling, convolution, morphological operations). The NaNs will propagate through to the result image and indicate unknown values in exactly the correct way, without having to do extra work. For example, a convolution will widen a single NaN to take in the whole footprint of the convolution kernel. A scaling will just pass the NaN through to one pixel in the output. There is no analog of this property of the NaN for integers.