For a little personal historical perspective:
I first learned about multiple dispatch about 20 years ago in college when taking an AI course that required common lisp. Although common lisp itself doesn’t have OO, the extension (via macros) CLOS (common lisp object system) is a form of OO with multiple dispatch (BTW:I think Julia got it’s inspiration from CLOS). I remember when I first learned the CLOS OO way I thought “wow this is so much more elegant and powerful than C++'s way”. But like most cool things you learn in college this remained a one time experience and in professional life, OO was the C++/Java/C#/… way.
About 10 years ago I learned Clojure and as a lisp descendant it also has multiple dispatch (called multimethods). So when learning about multimethods (which is totally alien to Java programmers) I remembered my Common lisp experience and recognized it as the system from CLOS. When I learned R some years later I recognized the lisp influence and the multiple dispatch (in S4 system).
So when I first learned Julia the multiple dispatch feature wasn’t unfamiliar and didn’t come as a shock and I was fine with the fact that Julia’s OO isn’ t the obj.method syntax (unlike some people who come from Python and regularly demand this).
What is different with Julia from those older systems is the multiple dispatch is a much more central feature of the language and the libraries whereas in the other systems it’s more “bolted on”.