I've thought about this in relation to 'old' media. When I used to write headlines for newspapers, the purpose of the headline was to get the reader to read on. In the case of the front page headline, it often meant the difference between the user buying a newspaper or not.
I wrote the best headline without distorting the truth, but the more enticing I could make it the better. In that respect, I don't think clickbait is any different. However, clickbait has come to indicate that the content doesn't live up to the value suggested. It got so bad that Facebook penalised purveyors of clickbait.
Also don't forget that a click can have many purposes. In my world, I would like to think that I provide value behind my clicks, but others could quite easily just be generating traffic, for which they can charge advertisers.