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.