I found that with CGI::Application, and similar Perl modules you get the facilities of the modern stuff, as well as the portability and simplicity of a simple index.cgi script.

Two things I think Perl always had a good reputation for was CPAN, providing interfaces to "everything", and a high degree of testing. I love that golang and rust both emphasize testing in modules/crates/packages. Writing perl CGI scripts I always had test-cases for the whole lifecycle, and that's something that isn't so common these days writing handlers in other languages.