@simon Catalytics converters increase fuel use. Fuel is expensive. Other people's lungs are worth nothing to Musk.
@nickalt that's interesting, it would suggest that there's an increase in CO2 output from running those devices, as a trade-off for reduced NO2 etc
@simon @nickalt Yes. A catalytic converter restricts the exhaust flow, so some of the engine’s power needs to be spent forcing the exhaust gasses through it. This results in higher fuel consumption. It’s normally a very small amount of power (and therefore a very small amount of added fuel), though. Catalytic converters are expensive, which I suspect is the more likely reason they were omitted.
Incidentally, stricter catalytic converters can actually be beneficial for certain engine designs like Wankels. Backpressure in the exhaust helps prevent those from blowing out their apex seals, especially with forced induction.