I'm very much in agreement with objects-as-named-params. Default params just mitigate the problem, ambiguous function calling still rears its head as soon as you have multiple optional arguments of the same type.
As to the "option = option || {}", he was referring to the ultimate "option = {}" assignment if you passed a falsy value (0, "", false), which is different than if you didn't pass a value (undefined). Which is resolved by "option = option === undefined ? option : {}", which is even larger and kinda ugly.
Ahh, I see. The thing is, I can't think of a single way to make {} be treated as false in the boolean context, so 1) I don't think you'd ever need anything more than "option = option || {}", 2) I think the example would have been better off using an integer or string where you actually might have to use the ugly long format.
EDIT: Unless of course you get some non object value passed in and you want to be sure to keep it regardless of whether or not it is falsy. Not sure why you'd want to do that -- I am sure I would NOT like to see someone do that if I had to deal with their code.
As to the "option = option || {}", he was referring to the ultimate "option = {}" assignment if you passed a falsy value (0, "", false), which is different than if you didn't pass a value (undefined). Which is resolved by "option = option === undefined ? option : {}", which is even larger and kinda ugly.