That reads like an argument for static type checking languages and against runtime dynamic languages, and I'm generally in the same camp as you, but obviously i

That reads like an argument for static type checking languages and against runtime dynamic languages, and I'm generally in the same camp as you, but obviously it's not impossible to use either to write a good program if it's only 1000 lines (they also state they use shellcheck, which is not nothing). There's absolutely something to gain from their approach. And shell is not particularly cryptic, it's just taught awfully -- the main problem being that lazy tutorials just don't mention how quoting/tokenizing works. Using shellcheck almost always pushes you in the right direction.