yes - you do 4 weeks and you are qualified. That helps explain why there are so many poor tefl teachers around.
Being a qualified teacher counts for nothing unless it comes with a "graduate" label. Some employers and most government departments of education are not enlightened [to put it politely], so they think a degree in media studies or marine biology means you can teach English - look at the majority of job offers on the net: the first thing they state is "graduate" .. good for status and impressing punters. One of the most popular teachers where I worked recently bought his BA in Thailand but his CELTA was legit.