I think the idea to use the environment is misguided in general.
The environment was only ever good for things like GOMAXPROCS where you want a single point of truth for all processes on a machine but in a containerized world even that point is moot. Where regular config in the environment just problematic it is outright dangerous for secrets.
I won't disagree that it comes with security tradeoffs and depending on the situation it can definitely be a problem. But in many cases with how people deploy lots of software - most PaaS and things like lambdas / cloudflare workers, etc - it's absolutely fine. With varlock, we can even swap out the secret delivery mechanism at the end - but you still get a schema and familiar interface for how it all works.