I could be mistaken, but from various sources I have come across (some of which I have linked to previously) a C-130 aircraft Rapid Dragon weapon pallet can have up to six JASSM-sized munitions, with up to two pallets fitting aboard. A C-17 Rapid Dragon weapon pallet can fit up to nine JASSM-sized munitions, and have as many as five such weapon pallets.I agree with the above, add to that, the article states, due to the configuration, that the MC130J actually carries more palletised weapons than the C17 does. Long range missiles are cheap compared to fighter aircraft or bombers, and using transports, frees up the FGA and P8 fleet for other jobs.
the range of the C130s and c17s is around 3000 km and 4000 respectively, giving a huge reach. just having the palletised systems in place weather they are used or not, gives flexible contingency, at a relatively modest expense.