"it would be incorrect to say that the bit has a value of, say, 0.5 during the transition."
In what sense? It has a <z>=0, meaning there's a statistically 50%/50% chance of measuring 1 or 0 but the system is in principle coherent.
This means that half way through the jump, if you rotated it 90 degrees, you'd measure a _definite_ z value of -1 or 1, or you'd measure a bit value of 0 or 1, depending on whether you twisted it clockwise or counterclockwise.
In the sense that it ignores that coherence. Any state on the disc of the Bloch sphere's equator has <z> = 0, and 50:50 chance of measuring 1 or 0. If you want to assign a real value of 0.5 to a bit, then the only one that makes sense is the center, completely decoherent mixture.
In what sense? It has a <z>=0, meaning there's a statistically 50%/50% chance of measuring 1 or 0 but the system is in principle coherent.
This means that half way through the jump, if you rotated it 90 degrees, you'd measure a _definite_ z value of -1 or 1, or you'd measure a bit value of 0 or 1, depending on whether you twisted it clockwise or counterclockwise.