1967brutus

I am unfamiliar with WIB, never even heard of the name, which is a bit weird since I am in engineering for about 30 years.
I cannot tell you about the "why", I can only tell you what my experience has invariably been with the known brands like SKF, NSK, Nachhi, FAG, and all those. They all do as I said.
I never said anything about cranks spinning in the inner ring, and to my knowledge, I have never seen signs of that happening in model engines.
All I can tell you, is that when pulling a regular model engine apart, if the rear bearing taps out with the shaft, it was either not a C3, or the seat in the casing has been mistreated/damaged or really extreme cases corrosion or castor residue made it stick to the shaft.
This even is valid for the few Saitos that OEM use "normal" rear bearings: the bearing comes out with the shaft. I did a Saito 80 this summer, and was amazed that that particular bearing size is not even availlable in C3 (I never buy "original OEM" in the engine branded packaging).

But I am pretty sure, that if anybody would send me a regular and a C3 bearing of the WIB brand and I would compare them side by side on the same engine and crankshaft, I will see the same results as I see with all other bearings.
Mind you, with the stuff I have at my disposal for measuring (Inner diameters to roughly 0,01 mm accuracy) I cannot tell a normal bearing from a C3 with any degree of certainty. But when mounting them on a shaft, I actually CAN tell them apart. C3 invariably is the one that fits the shaft easiest, and as said, at times being the difference between a slide fit and a press fit. That's how marginal these differences are.