it's not really like a 'live axle' from an older truck, it's more like a de-Dion style suspension (or dead axle).

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

you still see these in velocipede-style vehicles commonly.

and to your point : a dead axle is an effort to reduce unsprung weight compared to a live axle; it also lets you actually use alignment as a remediation for asymmetry issues rather than just pre-delivery straightening.