Rust has a combo: people come for safety, stay for usability.

Languages struggle to win on usability alone, because outside of passion projects it's really hard to justify a rewrite of working software to get the same product, only with neater code.

But if the software also has a significant risk of being exploited, or is chronically unstable, or it's slow and making it multi-core risks making it unstable, then Rust has a stronger selling point. Management won't sign off a rewrite because sum types are so cool, but may sign off an investment into making their product faster and safer.