No, I didn't want to be a mini castella vendor, but I probably couldn't have been had I wanted to.
Many people believe that the country is your oyster in terms of work if you learn to speak, read, and write Japanese and are a foreigner. Many people are wrong. Under certain circumstances and if you are completely fluent, you may be able to do a particular job or two that a Japanese person would do. However, it is overwhelmingly the case that foreigners are hired because they are foreigners. They are not hired to do work that a Japanese person could do because, frankly, the Japanese would rather work with known quantities rather than a cultural wild card. There is also the fact that, unless you are a permanent resident, you can't legally be hired for a job a Japanese person is capable of doing. You have to possess a skill they do not (though this law is often ignored if the foreigner will work for a lower wage than a Japanese person).
For all of the reasons above, the range of jobs that a foreign person can reasonably do in Japan is quite limited. The same may apply to every country in the world, but I was a foreigner in Japan and this is part of that experience that I will not miss.