In my days in another province, I knew a goodly number of IELTS examiners. The ones that I knew were all British, 45 years of age or over; only one was truly a Cambridge University trained scholar; one was an ex-British Telephone lineman (believe it or not) who managed, somehow, someway, to crawl to the top of the heap in that city and become a DOS in a large private school (without a university degree). In that province, it was an oh-so-clubby, so-chummy, so very British private club (the IELTS examiners). It was very, very lucrative, lots of busy week-ends, etc. Those few North Americans that I knew that worked as IELT's examiners in that province found the atmosphere stifling, overbearing and well, somewhat pompous (their words exactly not mine). I was afforded the opportunity to be an IELTS examiner but politely declined. Personally, I don't do well in what-appear-to-me to be 19th century style English private clubs. Lack of oxygen if you will.
Anyway, yes, it's lucrative, no, it's not for everyone, yes, it plays to politics a great deal and four, there are other opportunities far more socially amenable that are available to Americans. To each his or her own, however.