Concrete answer? then this is for the Government of El Salvador to answer and this will surely explained once it happens.
I would call it as a helicopter money. Government will distribute these $30 worth Bitcoin and citizens will immediately spend it (just an inner feeling). Only few will hold. Government will quickly get back these $30, but they will be remembered for a long time for such generosity.
Anyway, free money is free money. Any money and support from government is encouraged. I'm glad that they come up with idea of such distribution.