The general use case is pretty clear: many people currently have secrets (passwords, API keys/tokens, etc.) hard-coded somewhere, whether it's in their actual source code repositories, build scripts/tooling, or just dumped into environment variables or build configuration in their CI system. That's bad for a number of reasons, mainly because (1) it's very likely to allow disclosure of secrets to unauthorized parties (i.e. see tools like
gitrob), (2) it's pretty much impossible to audit use of the secrets, as anyone who can read the code/config can get them, (3) it's very painful to change them, as that most likely requires searching large amounts of code or config for the actual secret, and (4) those secrets are generally static or not rotated often, so disclosure of them even days, weeks or months after a job is run can yield unauthorized access.
It currently takes a statically-configured token, which is very bad security practice from a Vault perspective; we have an
open, apparently slated for the next release, to support reading the token from a path on disk, such as the file written by HashiCorp's (Enterprise) Vault Secure Introduction (VSI) client.