Earlier quoted context omitted.
Denial of your opponent’s access to the battlefield is “table stakes” in the next war. I assure you — all terrestrial and major satellite up/downlinks will cease within minutes of the next major conflict starting.
Well, in case of a global thermonuclear war I think we'll have bigger problems than some transactions being reversed.
Undersea cables are easy to cut. Land based lines are easy to cut. Unless the locations of these cables are well hidden (which I don't believe they generally are), you could easily severe all of a country's internet connections in a couple of days.