Right, so CGI is quite old by now, which is basically this: a binary in a directory and a proxy that throws packets at it.
It has its pros and cons. In some cases it's actually quite nice to have a platform like Wildfly or the BEAM, or you knew so little about the future load peaks that you started with cheap shared hosting and hence PHP so when you outgrow it FastCGI and nginx is a much better option than a great rewrite to Golang.
Building in the languages and on the platforms you already know will always be much faster and more convenient than betting on someone else's 'bees knees'.
It has its pros and cons. In some cases it's actually quite nice to have a platform like Wildfly or the BEAM, or you knew so little about the future load peaks that you started with cheap shared hosting and hence PHP so when you outgrow it FastCGI and nginx is a much better option than a great rewrite to Golang.
Building in the languages and on the platforms you already know will always be much faster and more convenient than betting on someone else's 'bees knees'.