It can be depending on the application, where it's done and for who. Don't forget you will need several books with the names of artists and songs for people to see to pick out what song or songs they want to sing that you have. I would suggest you have at least 3 books so people aren't waiting to look at a book and get upset.
Do they still use books at Karaoke shows? I would have thought that it would be all done online now