the language of a rebate reflects the reality - that the gst is a regressive consumption tax and that low income people end up over taxed as a result of the gst (while the "middle class" is extraordinarily under taxed today in canada). a progressive and over due tax shift in canada would be to increase the gst rebate, because the poor continue to be over taxed, and to increase taxes on the middle class (who are under taxed) in order to pay for it.
changing the language from rebate to benefit obscures the fact that the purpose of the rebate is to balance out inequities in the tax system. it instead makes it look like a welfare check that could be cancelled by a future right-wing government, when it's meant to address the inequities caused by the fact that across the board consumption taxes are not progressive in nature.
frankly, it's the kind of harebrained bullshit that donald trump would come up with.
so, i will be continuing to use the language of gst rebate and will not be using the language of groceries benefit.