DrKhalsa,
Veer ji, what you say is true. The problem comes up when a person wants to check something by a particular guru or baghat. For example, if I am looking for something in particular by Kabir, things go faster if you have an index and can see the pages where Kabir's shabds are found. The gurus and baghats appear in various parts of SGGS, and their shabds are not all grouped together first by Nanaak, then by Arjan dev, and so forth.
Respectifully speaking of course.