what do you mean? looks like you are missing the point. The paper says that digest authentication was and is here it just hasn't taken off for usability reasons and suggests how to overcome those so it can be considered as a viable alternative to cookies

on the contrary it is very usefull since you cannot disregard the paper's educational and awarenes raising value by going through the pros and cons of each option which directly answers the OP's question who is looking for those alternatives