Bhagavad Gita, Chapter 9, Verse 25

Votaries of the Devas go to the Devas; to the Pitris, go their votaries; to the Bhutas, go the Bhuta worshippers; My votaries too come unto Me.

Where devotion actually goes seems to determine where the devotee actually ends up, real cause and real effect.

This lays out a real, direct correspondence, worship of ancestors leads to ancestors, worship of this source leads here. Nothing about the outcome is left ambiguous.