The key difference is the use case. n8n and Zapier are designed for integration automation for connecting apps and services together.
Flowctl focuses on operational workflows that require human approvals and inputs, things like database migrations, infrastructure changes or scheduled maintenance tasks.
n8n has some permissions features, but approvals aren't built-in. Zapier is cloud-only and expensive at scale. Flowctl is fully open-source with no enterprise only features.