[Nyororin]

I would say that all that passing the test means is that you could pass the test.
I know that sounds strange, but I`ll explain.

I know quite a few people who have passed high levels of the English proficiency test in Japan who can barely speak English - However, they studied for the test, and passed the test. They have the ability to pass that level of the test, but not to actually USE and converse at that level.

Although it`s nice to be able to show that you have passed some level of the JLPT (if it were worthless, I wouldn`t have bothered taking the lv 2 and then lv 1) , in a business setting I would say it really comes down to how much real ability you have.

Conversational Japanese is the ability to convey what you are trying to say in ANY way that is comprehensible to the other party. Say, for example, if you don`t know the word for something, you have the ability to describe it in a way that is accurate enough to convey the meaning. ie. "Red truck with sirens" meaning "fire truck". Or... "Place where you mail letters" for "post office". Even with a relatively sparse vocabulary, someone can have a conversational level of Japanese.

Think of the way a small child speaks - it doesn`t stop them if they don`t know the word for something. They just describe it to the best of their ability, and it still sounds "natural".