With high unemployment in many English-speaking countries and a recession that doesn't want to go away, the demand for ESL training is buoyant. The macro prospects for work, however, are not looking particularly good in many places- Europe is economically squeezed in many parts and ageing, the population of Japan is already shrinking, Korea's will follow suit in a few years, and China 's working population is set to peak in a few years.
There are plenty of jobs to be had, but there are also plenty of applicants and I know well-qualified friends who have had to struggle to find work. You may be able to apply for jobs with other certificates, but it is blatantly obvious what employers are looking for. In the eyes of employers, CELTA is the standard, Trinity is a respected junior partner, and the rest at best are also-rans. You could run a similar test and get slightly different results, but these would be minor variations rather than very different pictures.CELTA named: 31CELTA/Trinity CertTESOL named: 29No qualification specified: 32No qualification required: 8(TEFL International named: 0)
Categories: General

This is particularly relevant in the UK where schools are accredited by the British Council which stipulates that teachers must have a CELTA or Trinity TESOL qualification. Those spending money on online courses hoping to get EFL teaching jobs in the UK are just wasting their time.
i have not done an all over the world comparison but i have noticed that in turkey the jb ads usually mention both CELTA and TEFL. i think in certain areas certain certificates might be more popular for no specific reason... and in Turkey certainly one might even get a job without a certificate, they would just like to see some kind of a paper to tell their clients that all their teachers have a certificate.
Dave's ESL cafe job listing has a lot of jobs in Middle East where i just compared now and saw TEFL mentioned a lot
http://www.eslcafe.com/joblist/
for general purposes CELTA is probably better suited as you suggest. but for someone just needing a job right now, in Turkey for instance, with not much money to spend on a CELTA course, its good to know an online TEFL is quite enough.
A fair number of employers won't consider you for a job if you have an online course, so I am not saying that an online course is quite enough. I said there was no evidence of online courses being a positive, meaning that no one asks for them by name, and some evidence that they were negative, menaing that people went out of their way to state that they wouldn't consider any online course.