Secret management is as complex as the system which relies upon it. Vault is not as easy as many other tools designed for simple systems. GPG by itself is often enough to manage secrets.
There are probably 40 or more secret management solutions out there, many tailored for specific uses. Most CMS's have their own secret management baked in. Most orchestration and infrastructure tools do too. Four different solutions are called 'Vault'. There are at least 5 solutions just for Amazon. Depending on your platform, something other than HashiVault may be easier to adopt.
Here's some reviews of a dozen different solutions: https://gist.github.com/maxvt/bb49a6c7243163b8120625fc8ae3f3... https://medium.com/on-docker/secrets-and-lie-abilities-the-s... https://www.threatstack.com/blog/cloud-security-best-practic... https://www.youtube.com/watch?v=OUSvv2maMYI&feature=youtu.be