Center of the coordinate system is chosen by the scanner’s operator. It often contains somewhat useful information that is should not be simply discarded. Erasing the information would also make the volume spatially misaligned with other data structures that are defined in the same coordinate reference.
“Center volume” irreversibly erases image position and orientation, so it should not be used. This option was added decades ago and we haven’t removed it, because it is quite hidden and so unlikely that people would find it.
If you want to automatically fit templates to an image then image bounds are not ideal for this anyway, but you want to do a simple analysis of the image content instead. For example, if you apply simple thresholding then oriented bounding box or principal axes will tell you the physical location of the chosen object within the image.