It is very simple, really: Because the rich and powerful are back in power. The rich and powerful do not like Reais, they stash their money and profits away on tax havens. Let’s say you are rich and powerful, your money is all hidden away in the Cayman Islands, and now you run Brazil again. What would you do? Well, it makes sense to devalue the Real as much as possible. This makes you much richer in Reals, and allows you to buy anything you want, including the dumb competitors who forgot to stash their money somewhere else. Also, if you are one of the smart rich folks, you don’t dabble in the internal Brazilian economy, that is too small, its better to be an exporter. As an exporter, once you devalue the Real, your costs are lower, and you get paid in dollars!
Fun stuff! Don’t be a fool, keep some of your money in US dollars.