We turned a low pocket pair into a multi-street bluff on a scary board, only to bink a set on the river for a pure value shove.
Raising here is a high-variance play. While we have a backdoor flush draw, calling is the preferred way to realize equity with our bottom pair.
Note: Raising bottom pair on this wet board is overplaying our hand; calling allows us to see turns cheaply and realize our equity.
Once we've represented strength, the Ace is a mandatory barrel card. It's the best card in the deck for our perceived range to continue the story.
The river 3h is a miracle card, giving us a set. With the SPR so low, we have a trivial value shove to get called by any remaining Ax or two-pair hands.