I never (ever) used a tad to mind control, never ate one of extra pods, and tentacle dude from a prism still said i need to transform further and gave me a frozen super-duper pod to do so.
never used it, have no intention to.
act 3, never had ANY consequences to not eating tads.
Seems like exactly what I predicted. You get huge benefits from using (and now eating) the tadpoles but squat from refusing to do so, which is utterly lousy game design.