Ivyman
Teaching abroad has benefits, sure. Learning about and experiencing a new culture, picking up language skills (you won't get this from teaching, but if you want to put effort in to learning you'll certainly be in the perfect environment for it), making new friends, gaining a broader world perspective, all are potential benefits of living abroad, no matter what you do there. Teaching in China is what you make of it. Lots of people can turn a stint in China into a lifetime career. Some people take what they learn in China and branch off into other avenues -- business, consulting, translating, writing, etc. Others will teach 15 hours a week at the local uni and feel like they've got it made. A lot of what you make in China will depend on your own drive, your connections, your skillset, and finally, your funds. You can't really make anything happen business-wise in China without money.
And on that note, no, teaching English in China does not really give you any transferable business skills. You can learn Mandarin without teaching English. In fact, the best way to learn Mandarin is probably not to be a teacher but to come over here as a student. Unless you plan to stay in education, your experience teaching English in China does not really transfer directly to any one field. That doesn't mean there aren't benefits, but the benefits are mostly intangible. You have to really be able to take your experience and mold it into something else, if that's what you want to do, and you really need to have some sort of marketable skill that sets you apart from the crowd.
As an example, I have a friend who started out as an English teacher, moved to a management position at a training school (she got this position because she's very type A, very organized and thorough, and really busted her ass at a job where lots of people are really phoning it in), was able to move to another management position with a large tech company (to make a move from teaching to not teaching you have to be willing to worker harder than anyone else, humble yourself, take a salary that might not even equal what you make teaching, and be very good at self promotion), learned skills on the job at the tech company, moved to another tech company as an operations manager, then was able to get posted back to America with the company that hired her. She's now making close to 6 figures at home, and this started with a job that paid her basically the same amount that I make as a teacher in Beijing. It was no easy task though, and every step of the way she had people who looked down their noses at her for her roots in English teaching. It is much easier, in a sense, to start out not a teacher, and go directly into business, if you have the ability. Using English teaching as a springboard to other things is an uphill climb and it is a climb that most teachers do not succeed at making.