Bend protocol uses the same interest model as AAVE's aToken. You can easily understand bendETH if you know AAVE's aToken well. The core value of bendETH and aToken are the same. (You can check the Reference.)
The difference between bendETH and aETH is the liquidity on Uniswap.
BendDAO's bendETH is the interest-bearing token minted and burned upon deposit and withdrawal. The bendETH balance value is pegged to the value of the corresponding deposited principal with interest and can be safely stored, transferred, or traded.
Users can import the bendETH token into wallets etc. MetaMask, use it as a normal ERC20 token.
All interest collected by the bendETH reserves is distributed to bendETH holders directly by continuously increasing their wallet balance.