I have read several Hashicorp Vault tutorials and one of the features that could be used is generating ssh keys for git clone repositories, but that implies that everybody in the company that clones repositories should install vault and an helper like https://github.com/hashicorp/vault-ssh-helper
In the hope of resurrecting this question, I will give my opinionated answer.
As I understand it, the use of Vault is part of the drive to give more autonomy to teams, by removing fear of leaking or changing secrets. By providing somewhere to store and manage secrets, ops can give dev the means to continue developing at their own pace, following the practices of continuous integration and working in small batches.
With a product like Vault in the pipeline, secrets can be consumed safely in the various phases - build, test, bake, deploy, etc. Implementing Vault in practice means less personal interaction with the service, but more machine interaction with the service, from trusted components in the pipeline.