Why an agent would refer instead of list
A house needing extensive repairs, a seller in genuine time pressure, or a situation where the agent's brokerage doesn't handle direct/as-is sales are all real reasons an agent refers a client elsewhere rather than taking a listing that isn't the right fit.
What has to be disclosed
Any referral relationship and fee arrangement should be disclosed to the client per the agent's professional obligations — this isn't optional, and a straight arrangement puts it in writing upfront rather than leaving it implied.
What this looks like from the seller's side
A seller referred this way still gets a direct cash offer evaluated on its own terms — the referral fee is paid by the buyer to the agent, not deducted from what the seller receives.