Natural gas is significantly dirtier than nuclear, and hydrogen (in terms of how we use it) is a component of an energy storage technology and not a fuel source.

But significantly cleaner than oil and abundant enough to make an impact much sooner.

Impact in what? It still releases carbon dioxide into the atmosphere.

Way less carbon dioxide per joule produced, also, no sulfuric dioxide.

Reducing and replacing gasoline/diesel usage.

LNG powered cars have been available for a long time. They never caught on (speaking from a Swiss perspective). Whatever the reasons may be: Less dynamic driving experience, not enough LNG gas stations, expensive to retrofit, no cool new cars, no that much cheaper compared to gasoline - the consumer apparently just doesn't want them.

Natural gas isn't much better than gasoline, biogas is a good option but the production capacity is limited at best.

Hydrogen won't be viable for consumer vehicles unless we get a Hydrogen Elon Musk who optimises the production efficiency by 500%. (It takes around 55kW of electricity to produce the hydrogen needed to get 11kW of energy from a fuel cell vehicle).