You are considered a writer when you start writing essays/articles. You don't have to pay your $50 and you will still earn.

However, there are several reasons why you should pay your $50.

1. The writers only earn when you pay. Otherwise you are reading their articles, gratis, and this means they struggle to earn a living. About 95% of Medium writers earn less than $100 a month.

2. Your work is more likely to be read if you have paid that $50 because some people will not read you if you haven't paid it.

3. Your work is distributed to people who are not your followers. Believe me, you need at least 1000 followers before you hit $100 a month.

Hope that helps.