Another primary consideration in introduction & eventual disappearance of Segmentata?

[Urselius]

I think that there are some indications - in Zosimus and Ammianus, possibly also Vegetius could be interpreted in a similar way - that the infantryman of the Dominate was expected to fight in light equipment - i.e. no body armour - as well as in body armour. This would depend on the circumstances; a raid, such as Julian made on the Rhine islands, would not have required armour, indeed jumping in and out of small boats it would be a positive menace. In contrast, the Principate legionary was required to wear armour even when engaged in engineering projects, when close to the enemy - as can be seen on the columns in Rome. The abandonment of segmental armour may have more to do with its transport bulk than anything else. A soldier expected to switch from armoured to unarmoured fighting can transport a folded mail-shirt much more easily than a segmental armour, even if the weight is similar. Even when concertinaed, a segmentata is still more bulky than a folded or rolled mailshirt.