Casey:
The reason your parabolic blades don't "look" thinner anywhere is that the blade thickness differences are mostly on the order of .001 to .002 inch. You can use a very good calipers or a micrometer to accurately measure it. (That may be less than the depth of surface scratches.) And of course, we spend most of our time on one edge, so all that really changes is that the edge angle would be a little thinner (effectively marginally sharper) where the blade is thicker (at the ends on a parabolic blade) - by a possibly insignificant amount.
(A question I haven't answered is whether the entire width of the blade sinks into the ice during take-offs and landings - in which case a wider part of the blade might be very marginally more stable at those times.)
Also, your figure comes from Paramount. We can't assume they measure MK and Wilson blades accurately, especially since MK and Wilson blades vary a fair bit from the factory, so you would need to average the results from many blades. (Also, because of the imperfect way the most common rocker measurement tools work, taking 3 height measurements offset a little ways from the side of the blades, any type of side honing would make those measurements somewhat inaccurate.) There was a somewhat similar figure years ago on the Wilson website, from when MK and Wilson were two fully separate competing companies - I'm not sure whether they showed the same measurements. And I've never seen published specs from MK itself.
Those pictures are what I meant about spin rocker curvature being different from the main rocker. The Wilson website used to say that Wilson blades had two different spin rockers in different parts of the blade, as on the Pattern 99 in your figure, though that isn't consistent with what it shows for the Gold Seal.
BTW, spin rockers are often deliberately modified in radius and placement by high end sharpening pros, to meet the needs of the skater. (Most lower end sharpeners don't deliberately try to modify rocker profiles.)
Something your picture doesn't show is that many MK and Wilson blades have somewhat shorter rocker radii (are more curved) near the tails (maybe, 6') - I'm not sure if that is deliberate, or a machining error.
Side honing isn't new and revolutionary. Figure skating books were debating the merits of various forms of side honing, without clear resolution, from at least as early as the late 19th century. And all these things, and others like scalloping, have been used in fancy knife blades for a lot longer. The conclusion is clear: if you like the results you think you get from any form of side honing, you should get them, because you will be happier to know that it was done.
If what I believe is true, that the main effect is psychological, it makes a lot of sense for "Parabolic" to be printed large. That marking may be the principle thing you get from paying extra for such blades.