At what point does Dispatch make more sense than Galvanic Blast?

[[Dispatch]]

[[Galvanic Blast]]

I've been thinking about this recently, as my FNM is almost always Modern, our meta has a lot of creature based decks, but Galvanic Blast is becoming less and less reliable as removal with

Gurmag Anglers, Tasigurs,

Goyf, Finks, Predator Ooze

Master of Waves,

and most recently, Martyr of Sands combo with Serra Ascendants and Auriok Champions among other things.

is the non-metalcraft downside to dispatch so much worse than Galvanic Blasts?