According to this Bloomberg article, some of them are suspicious of it:
a poll last week by El Salvador’s Universidad Centroamericana Jose Simeon Canas found his Bitcoin law is widely unpopular. Two-thirds of respondents said the law should be repealed while more than 70% said they prefer to use U.S. dollars instead.
But it looks like the government is giving people pre-loaded wallets with $30 worth of bitcoin if they sign up with their national ID. It's free money, I imagine most people with sign up.