I basically agree with you that this is just a symbolic victory... but sometimes symbolism is very important.
This is a shot across the bow of the EPA mothership.
Of course it won’t bring the ship down... but it very well might be “the shot heard round the country”.
And not only that, it provides a way for every Texan to participate in the revolution, just by going down to the store and buying a light bulb.
Mere symbolism? Again, yes. But very powerful symbolism it is.