Brazilians being Brazilians it is quite likely that this will create an incentive for people to start using illegal apps.
E.g.: in Brazil abortion is illegal but quite common, tax evasion is illegal but quite common, smuggling from Paraguay is illegal but quite common, gambling is illegal but quite common, ...
It's very hard to make those applications actually illegal (the Congress literally does not have the power for that).
More likely, the government will regulate any company distributing them out of existence, while foreign companies and software-only protocols will get the entire market.
E.g.: in Brazil abortion is illegal but quite common, tax evasion is illegal but quite common, smuggling from Paraguay is illegal but quite common, gambling is illegal but quite common, ...