Gravitational entanglement: Evidence for quantum gravity or a problem for causality?

Conceptual difficulties with the idea of gravitationally induced entanglement as a proxy for the quantization of gravity are discussed from various perspectives. A toy model interpolating between the Galilei-relativistic limit of mean-field semiclassical gravity and a de Broglie-Bohm description of Newtonian quantized gravity is presented as an explicit counter-example to claims that witnessing gravitationally induced entanglement between two particles would constitute a definitive proof for the quantization of the gravitational field. Furthermore, it is shown how - combined with prevalent heuristic ideas about the coupling of complex quantum systems to curved spacetime - the idea of gravitational entanglement poses an apparent conflict with relativistic causality, whose potential resolution points towards a novel decoherence channel for light-matter interactions due to gravitational effects.