One unique and new feature of Slang that sets it apart from existing shading languages is support for differentiation and gradient computation/propagation - while still cross-compiling generated forward and backward passes to other, platform-specific shading languages. Before, the only way to backpropagate through shader code (such as material BRDF or lighting computation) was to either manually differentiate every function and chain them together, or rewrite it in another language or framework - such as PyTorch or a specialized language/framework like as Dr.Jit, and keeping both versions in sync after any changes. Game developers typically don't use those, programming models are different (SIMT kernels vs array computations), it's a maintenance headache, and it was a significant blocker for a wider adoption of data-driven techniques and ML in existing renderers or game engines.