I'll run Apache till the end.
For me, the main draw to nginx was powerful (web) proxying, static file performance and simpler configs - Caddy does all of that 10x. In a sense, nginx is right in between Apache and Caddy, so unless I need to proxy something obscure like RTMP or email, I rarely have a use for it these days.
HTTP is not new technology, nor rocket science, a web server to serve a simple HTML page should be configurable from scratch, from an empty .conf file, in seconds.
Caddy seems to share the same philosophy.