Sure. University / Government sector. I know quite some unis/projects in that field that switched to caddy, since gigantic ip ranges and deep subdomains with stakeholders of many different classes have certain PKI requirements and caddy makes using ACME easy. We deploy a self serving tool where people can generate EAB-Ids and Hmac keys for a sub domain they own.

Complex root domain routing and complex dynamic rewrite logic remains behind Apache/NginX/HaProxy, a lot of apps are then served in a container architecture with Caddy for easy cert renewal without relying on hacky certbot architectures. So we don't really serve that much traffic with just one instance. Also, a lot of our traffic is bots. More than one would think.

The basic configuration being tiny makes it the perfect fit for people with varying capabilities and know how when it comes to devops. As a devops engineer, I enjoy the easy integration with tailscale.