In Satpy extra information is copied to the X and Y coordinates that are added by the resamplers. See:
https://github.com/pytroll/satpy/blob/0b2be453b412f74db7b4c39ee9ac21372d87ff39/satpy/coords.py#L77
With the KDTree/nearest resampler however it sees that coordinate variables were already added by the upstream pyresample resampler and does nothing further. However, pyresample is missing some important information that is easy to obtain like the "units" of the coordinates. This can be taken from the CRS object as it is done in the satpy versions of these functions linked above.
In Satpy extra information is copied to the X and Y coordinates that are added by the resamplers. See:
https://github.com/pytroll/satpy/blob/0b2be453b412f74db7b4c39ee9ac21372d87ff39/satpy/coords.py#L77
With the KDTree/nearest resampler however it sees that coordinate variables were already added by the upstream pyresample resampler and does nothing further. However, pyresample is missing some important information that is easy to obtain like the "units" of the coordinates. This can be taken from the CRS object as it is done in the satpy versions of these functions linked above.