Oh, bullshit. Have you given any thought to the energy resources that would be necessary to control planetary weather down to the level of calling up targeted lightning discharges on demand?
And? It's just another drain on Vaal's resources, eminently something Vaal can't just shut down and forget about on a whim. It won't make it any easier for Vaal to shield its physical command center, quite the opposite.
Scotty can supposedly melt cities with those phasers, ever since "A Taste of Armageddon". It's just a matter of dwell time before he can collapse the defenses of what may amount to an entire planet but in practice is just a single shield bubble around a key facility. Apollo's temple, Vaal's snakehead, even Landru's mainframe should have fallen eventually, unless they actively fired back (as, again as per "Armageddon", maintaining shielding on the starship would in turn limit the ship's ability to go on the offensive).
The key issue here is that there isn't even demonstrable
correlation between Vaal being denied those delicious rocks and Vaal suffering a drop of potency. There's unlikely to be causality there, then. A constant slight drain is observed regardless of "feeding", and a major drop results from those continent-glassing phasers bombarding Vaal, which is what we really should expect.
It's a somewhat separate issue that we should
also expect Vaal to aim one of those lightning bolts upwards and incinerate the annoying starship, plain and simple. But again there's discontinuity between Kirk's wild tangents and Vaal's actual actions - and since Kirk doesn't speak Vaal, we may well assume that Vaal didn't really want to be all
that aggressive against people who had not yet demonstrated they would be a respectable threat. It may have been genuinely puzzled at why killing those redshirts didn't stop Kirk's offensive yet, and was holding the ship until deciding how to proceed; too little, too late seems its modus operandi overall.
Timo Saloniemi