It's not that unique - in Russian space school oxidizer-rich turbines are routine. Proton, for example, used to have - until latest years - a pretty solid track

It's not that unique - in Russian space school oxidizer-rich turbines are routine. Proton, for example, used to have - until latest years - a pretty solid track record, especially for first stage engines, and those engines use N2O4 for turbines. Considering that N2O4 is burned with some amount of (CH3)2N-NH2, making HNO3... the gas going to chamber from turbine is the nitric acid. Still engines work just fine. One of big reasons for Russians to use oxydizer-reach gas generators is that on the rocket there usually much more oxidizer - by mass - than fuel, which makes the flow through the turbine much bigger - several times. So efficiency of turbopumps goes up. That justifies the complexity of having oxidizer-rich gas flow before the chamber.