I think you need to keep the two issues separate. One thing is certification and another is immigration.
Due to a very difficult situation with obtaining work visa in the whole of the European Union, employers prefer EU passport holders to non EU passport holder, regardless of the amount of teaching qualifications they may have. Basically they look for teachers who do not need to apply for visa.
This does not mean you cannot work in Europe but simply that it may take you longer to find employment.
Being TEFL certified will certainly make you more marketable and it will also prepare you for the job.
CELTA is undoubtedly a popular qualification especially in Europe but it is also a fairly intensive certificate program in terms of finance, workload and commitment.
Training online is a viable option, despite what some supporters of traditional onsite courses claim. In fact online TESL/TEFL training has existed for many years. However as with all new things online TEFL courses met with a lot of resistance and preconception purely on the grounds that they were delivered online. Thanks to the ongoing efforts of those course providers like ICAL who have been committed to quality teacher training since the very beginning, the trend has changed, and even major universities around the globe are making the switch to online learning.
Many good schools around the world happily accept online TESL/TEFL Certificates issued by reputable organizations. So if you are looking for a way to get some basic training and a foot in the door, online training is an option worth considering.
Just make sure you choose a reliable course provider, and this applies to any course whether it is conducted online or onsite.TEFL Course Review
is a site where TESL/TEFL courses and course providers are independently reviewed and rated by those who have actually taken the course. It might help you separate the wheat from the chaff.