http://www.xsane.org/doc/sane-xsane-doc.html

XSane is a graphical scanning frontend for SANE (Scanner Access Now Easy). It uses the SANE-library to talk to scanners. This means that XSane does not support any scanners itself.

XSane is designed for acquiring images with scanners (there are other devices like cameras and videodevices supported by SANE and you will see that xsane may support some basic functions of those devices, but XSane is not designed for that purpose).