It depends what people are likely to want it for. I think that in the case of someone wanting a book of your songs, your assumptions are correct. People would just need the lyrics and the chords. However, if I got a Robert Johnson songbook, with only that information in it, when I was trying to get into his guitar style, I would be well miffed! Then I'd like the notes written out and some sound advice on how to copy those licks... Horses for courses.