It would be nice if they weren't ``Gee Whiz'' graphs.
A ``Gee Whiz'' graph is one designed to exaggerate the difference, and is usually done by starting the relevant axis (here, Y) at something other than zero. Here they start at 160/165 for a maximum reading of 200/205, thus turning a 10% savings into (for the unwary observer) a 50% savings).
I suspect this wasn't el Reg's doing; I expect they picked the graphs out of TFA.
(The ``Gee Whiz'' name comes from How to Lie with Statistics, by Darrell Huff (1954, and still worth a read).) [Note: I know nothing of the identically-titled book by Jordan Conner, out this year.]