I wouldn't be too surprised if she can do at least one energy attack with the souls she has collected.
I'm already imagining the destruction and casualties she could inflict with a tornado and a lava Homies in addition of those she already has.
The Soru Soru no mi has so much potential, we are from having seen the full extent of Big Mom's powers and how destructive she can truly be in battle.
And Kaido is certainely far from having revealed all his arsenal yet either.
For the same reason why Crocodile didn't use his sand tornados or blades against Luffy in their third and final fights, why he didn't make sure that Luffy was finished the two times he beat him, why Doflamingo didn't use Parasite against Luffy or Law except during his futile attempt on G4, why...
But Kid isn't Luffy, plus it's not like Luffy was all alone against Kaido until now, plus there is the Tama thing to complicate things and I didn't see Big Mom's story ending in Wano even without Tama.