A "panacea" is something that cures.every illness. 64-bit floats could do just that, in the cases listed. The cost of it may be higher than one cares to pay though.

And when the cure fails to be adequate, well, it becomes a band-aid, a temporary measure in search of a real solution.

IIUC, they're using the word itself correctly, but they mean "double precision is often used with the intent of it being a panacea".

Perhaps "placebo" was intended?