The 'Prompt for transaction decisions' switcher is used to control the appearance of the additional confirmation alert when you are making a decision to confirm or deny a transaction.
As some transactions may potentially be harmful to your account once accidentally signed, LOBSTR Vault by default asks for double confirmation at the time of transaction signing.
If the switcher is disabled, the 'Are you sure?' alert will not appear when you sign a transaction.
Be careful and use caution if you choose to disable the switcher. LOBSTR recommends leaving the switcher enabled at all times.