I think the real unknown here, there are thousands of formulations of "plastics" including ABS, and ABS here is likely a generic term makes for a good sales pitch, and they all have varying properties, where FG has maybe 8? variation. It certainly can bre very robust.

https://en.wikipedia.org/wiki/Acrylonitrile_butadiene_styrene

From a counting pennies manufacturer perspective, small runs might be cheaper out of FG, and large runs out of ABS.