Required to be in Japan to file application for COE?

Hey, hope you all are well. I had a quick question regarding the COE application process. I am looking to file an application for a J-Find Visa, and my nearest consulate (California, USA) requires that we have a COE before filing for the Visa. They advised me to hire an immigration lawyer to file for me as a proxy, and after speaking to one, they said that I'd need to be in Japan as a visitor when they file this application for me, after I provide the necessary documents while I am still in the US. I'm just a little confused because I thought hiring an immigration lawyer would keep me from having to visit Japan to file for the COE (I was just there), since, if I was in Japan, I could just file for the COE myself? Any advisory here? Thanks so much.