We use Azure Key Vault.. and I'v ealways wanted to check out HashiCorp Vault. The Dynamic Secrets is something I don't see in other tools. REALLY NEAT!
Depends on what you mean by storing passwords for humans. Vault is a secrets and encryption management system that validates/authorizes people/systems before giving them access to secrets. So it's not going to replace something like 1Password, but you could use it for LDAP, SSH, TOTP, things like that