One of the most-important considerations for any “real-world production shop” is to be able to continue running old stuff while gradually introducing new stuff. There is, in a word, “a gigantic gulf that is forever fixed” between “development” and “production!”

Very, very quickly, the inherent complexity of the situation exceeds the capacity of anyone to manage it without explicit controls. (Hair follicles are a very precious thing, as you too will soon discover if you are a male of this species.) Disk space, on the other hand, is extremely cheap. This is why you see some of the things that you do, especially in the Perl world. Perl is “where the rubber hits the road” in practical production data-processing.