Headlines (at least in mass media) have always been a hook to get the reader interested. Back when you had competing newspapers for sale on a stand, people would glance at the headlines and maybe buy a paper if it looked interesting enough.
There is no doubt that the headline is an important hook. Yet there is a difference between a deliberately vague or misleading hook (which I would consider clickbait), and one that conveys what the article is about.
I don't like watering down the defition of clickbait to mean any headline that gets the reader to click on it. That sort of definition is mostly an excuse for bad behaviour (e.g. misleading the reader).
