What does this “maths literacy” subject cover? And how does it cover it?
If mathematics topics are covered by description rather than hands-on practice, then I can hardly imagine a more stultifyingly counterproductive way of trying to improve numeracy. If, on the other hand, it’s watered-down maths covering just some elementary topics, perhaps its main role should be as a type of bridging course rather than an examinable subject in its own right.
Math literacy is mostly about applying, in practice, the math learned up to grade 9. E.g. how to plan a household budget, how to work out how much you'll need for making payments on a car or house, how to pick the most economic cell phone package, etc. If memory serves (I taught it for a few months at a remedial school!), it also investigated such problems as how to work out how much tile you'll need to cover a floor with given dimensions, or how much paint you'll need for a wall of a given size, or how long it will take to travel from one city to the next at which speed and how much fuel you'll consume in the process.
I.e. it is perhaps not at all a bad subject to take if you are going to go into a completely non-mathematical field - it addresses precisely the kind of everyday math problems everyone runs into sooner or later, and considering how many South Africans default on loans etc. one can make an argument that we can do with this kind of mathematical literacy.
The criticisms against it that Rigil Kent mentions are ones I have heard before, and they are probably quite valid. I have now heard from many sources that in many schools, kids are encouraged or indeed almost forced to take math literacy rather than math, simply to boost the school's pass rate and number of distinctions.
Another problem is that while math literacy teaches the kids skills that are genuinely useful, it's a good question how many of those kids ever actually use any of it in practice. In my experience, most people just never make any connection between what they learned academically, and real life. They KNOW how to work out a household budget, but in practice run out of money by the middle of the month anyway, because in practice, instead of using their math literacy knowledge, they just guestimate based on how desperately they want the new pair of shoes. :-)