I think it is useful, if you haven’t taught before.
I fell into teaching while backpacking about 6 years ago and last taught about 4 years ago. I didn’t do it then and it wasn’t necessary for finding work. Finding work was also made easier (unfairly I suppose!) as I am a native speaker.
In terms of teaching with confidence, knowing where to start and how to teach more professionally, it is a good idea.
I have just finished mine, they can be quite pricey.
I’m sure there are some bogey courses out there too!
You see to have very good English from your posts and appear to have the confidence also which is good. Being chinese, having that experience of learning English and having lived abroad will in my opinion make you a better teacher than most foreigners.
So good luck!