You allow the contract to move your tokens.
Tokens stay in your wallet.
When a buyer comes along the contract moves your tokens to the buyer and gives you the opposite token.
This is handy when you offer dividend-bearing tokens. This way you get your dividends for your tokens until a buyer buys the tokens.
Another use case is to permanently offer stablecoins. This way you have your stablecoins in your wallet all the time and still they earn money for you.
Use it as a single-sided automated market maker / liquidity pool.
If you want it to be deployed on any other network, I am happy to add it! Tell me on DISCORD!
Also you can easily check through the deployed contracts code and quickly figure it out without extra documentation needed.
It is really primitve :) Everything needed is on-chain.
The contract is static, has no upgradeable parts and no selfdestruct. it will be here forever.