The several important things about lisp that you won't find in other languages without learning lisp include (I'm considering all lisps here, including schemes):
- it's essentially a working implementation of the untyped lambda calculus, an essential model for thinking about computing outside of the Von Neumann architecture.
- It is a symbolic programming language which allows for unique ways of manipulating code as data. The only other programming language that I know of that offers symbolic programming to the same degree is Prolog (outside of computer algebra systems).
- The parens and prefix notation really are a powerful feature, despite being off putting to beginners. You are essentially programming an Abstract syntax tree. All programming language spend some of their time in this form, you just don't usually get to play with the code this way. This makes it incredibly easy to prototype ideas for languages and compilers in Lisps
The functional programming and meta-programming benefits naturally fall out of all of these. The reason metaprogramming is so powerful in Lisp is because of a combination of writing code in a tree structures and being a symbolic programming language.
The big picture reason that lisp is so great for people interested in better understanding programming is that it is a language that encourages you to write domain specific languages to solve your problems.
I'll be the first to admit that this is not great for real world software engineering, but if you want to understand programming better, it is essential.
I've found more recently I want to solve problems with domain specific languages, so I'm totally on board with that. I would say that making dsls to solve problems is a great way to engineer software, as the code is usually testable and you don't need to modify it. Sort of where functional programming meets solid. Maybe not the best approach if you're in a startup though.
Sounds like you understand the pros and cons of DSLs: If you have a high functioning, disciplined software engineering team, a good DSL can smoke your competitors. If you don't have such a team, a DSL can smoke you.
