BETH is a 1-to-1 receipt of irreversibly burning ETH, minted by submitting a burn proof. This by itself does not confer to it any inherent value except what is imparted by guaranteed scarcity and the associated cost of obtainment, but it can also be used for directly minting WORM according to a minting schedule descrbied in the latter token's page.
One pathway of obtaining BETH is by burning ETH. A burn proof is created in the process, which can then be used to mint BETH upon submission.
As the account that submits a burn proof and receives BETH need not be the same account that burnt ETH and generated the proof, this mechanism provides a way to privatise one's ETH by shielding its provenance from the general observer.
NOTE FROM ME: WE PROBABLY NEED A NEW OOV FOR THIS