Yes. My PhD was on applied ML. My current day job is at a center for AI. There are many people dimensions smarter than me -- but AI is all I deal with every day.

The reason for the nebulous concept is that intelligence is hard to define. Thus, in the past it was often defined by relating it back to human intelligence, e.g. "automating tasks that would require human intelligence to solve" and even the Turing Test.
But there are harder definitions of intelligence, such as Francois Chollet's paper.

It is definitely NOT correct to say << [AI] is just using some search algorithm with heuristics to make the search more "intelligent">>.
AI covers way more and goes far beyond search.