Essential? No. Helpful? Sure.
I think methodologies are MUCH easier to learn than how to code well. So I would definitely start there. Being an excellent developer will certainly be advantageous when applying for jobs and will make you a valued member of any team.
That being said, being familiar with different methodologies can also increase your value as an employee. Different companies will use different practices, so being familiar with them can only help you in the long run. Or in a situation I've faced recently - my company started transitioning from waterfall to agile/scrum - and the couple of guys who were familiar with that were leaned on to be leaders during that transition.
It's really like comparing apples to oranges. You should learn both and try to be good at both. I guess if I had to pick one for what's going to be most advantageous in the long run though, I would pick coding.