TLDR: EIP-7906 lets transactions include assertions defining permitted outcomes. If one fails, the execution effects are reverted.
One example scenario could be that you interact with a contract you believe claims an airdrop. With 7906 you should be able to assert that the transaction produce only the expected effects of receiving the airdrop, and if it instead were to grant a malicious third party permission to spend your ERC-20 tokens, the assertion would fail and the execution effects would instead be reverted.