You can have your ledger device plugged into machine A (at home/office/datacenter) running tezos-signer, connected over VPN to your baker machine B (in cloud). Using tezos-signer on a different machine is to create security by separation.
No, there is no way to bypass the requirement to ack a transaction. You would have to write your own ledger-tezos app to support this. It can be done, as the baking app signs blocks without interaction using the same key. You would have to code a new instruction to sign without user button.