Is an index better than keyword search? (I am not sure). But I far prefer digesting technical information in a searchable electronic format rather than hard copy. Makes it much easier to find information. I think that indexes often seem to omit (just what I am looking for) that is contained in the text.
But to get back to the core question; mainly for schematic capture; I am trying to remember how to de-select symbols or wires from a window selected group. I saw that posted somewhere but cannot find it…
IMHO index is better. Keywords are good if you know the technical terms used in a program, but if you are not sure of a term used, indexes are an easier way to eliminate what you are not looking for.
As we are moving to the primary format of the documentation being a website, I’m not sure how much an index makes sense (vs. search). An index to me is most useful in a printed manual where you can refer to page numbers. Open to ideas here (either on how an index could be useful on a website, or on how we can make search better)