The killer application of nested VM and/or container applications might lies in the realistic simulation and emulation of networked elements [1],[2],[3],[4].

[1] ViPMesh: A virtual prototyping framework for IEEE 802.11s wireless mesh networks:

https://ieeexplore.ieee.org/document/7763263

[2] Chapter 13 - ComNetsEmu: a lightweight emulator:

https://www.sciencedirect.com/science/article/abs/pii/B97801...

[3] NestedNet: A Container-based Prototyping Tool for Hierarchical Software Defined Networks:

https://ieeexplore.ieee.org/document/9244858

[4] Network Virtualization and Emulation using Docker, OpenvSwitch and Mininet-based Link Emulation:

https://scholarworks.umass.edu/masters_theses_2/985/