You don't need to

Lots of hagwon jobs go unfilled outside of Seoul metro area.

It's a good deal to get back on your feet financially, but it can be a little bumpy transitioning to a new culture and lifestyle, and the wage gains have unfortunately gone to instead pay for the rising cost of rent. But you can have an awesome social life.

I do recommend finding a smaller city or Jeju. Your money will go further than in Seoul. It's VERY worth looking into. If you're more adventurous, Vietnam seems to be the hot TEFL spot these days and I guess the money goes further there, but Korea offers a lot in terms of lifestyle and established foreign community