Still, different paradigms are useful, and one of the best things about Lisp is you aren't forced into one, and there's no threat of one being taken away from you. Coalton to me seems nice for people who like what it provides, it's nice that it exists, even though I don't see myself using it anytime soon since I don't personally enjoy working in that paradigm. There are two other non-type-proofs-paradigm benefits of static typing, but I don't really miss them in CL. The first is related to automatic refactoring tools, but Lisp has features to ease refactoring to compensate, and text-search methods for renaming aren't that bad (and even in Java necessary if you want to make sure you haven't missed reflection calls, though even then you can miss some) and anyway one can read the second edition of the Refactoring book that uses JavaScript if one needs convincing that refactoring can be done just fine even in a lower quality dynamic lang. The second is related to trivial conveniences like compile-time typo protection on symbol names, interface mismatches (like swapped function call argument order -- but failing to that indicates I have an unintuitive interface, and CL has many tools to help me make it better the simplest being keyword arguments), and faster assembly code. But SBCL's handling of the standard CL type system is good enough to get all of those things to a pleasing degree.