It can't really have "full-sized keys" (the implication being also that it's a "full-sized" keyboard), if it fits in the dimensions of the mini can it?
The Apple wireless keyboard is about as small as a keyboard can get and still be a proper "full-sized" touch-typeable keyboard. Any keyboard that fits in the same physical space as an iPad mini, is - by *definition* - going to be a netbook sized "mini" keyboard both in overall size and in key size.
This is just deceptive advertising.