Unsurprisingly it buys completely into the Hashicorp ecosystem (Consul, weirdo HCL configs, etc) which is a plus or minus depending upon your perspective I guess. Vault servers are also stateful, which complicates deployment (you can't just stick N Vault servers behind a load balancer).
If I had infinite time I'd consider creating a "SimpleVault" fork consisting of exactly one secret and storage backend, one way to auth, one curated workflow and make it run in a stateless manner. I'd probably also remove all the clever secret generation stuff, since 90% of applications just require a secure place to store secret blobs of data, as opposed to creating dynamic time-limited IAM credentials on the fly or whatever.