All of the work we do matters in the progressive movement, but we live in something called capitalism. It took me ten years of being a foot soldier in the environmental justice movement, the student movement, the peace movement, to realize that in a country without real democracy, the one thing that the employer class will respond to is when all the workers walk off the job and create a crisis. That, at the end of the day, is the most effective way to challenge unfettered corporate power.
While I think all the issues matter, the foundation of power that is required for the rest of our issue-driven movements to succeed is a strong labor movement.