Having type checking is indeed a matter of preference. I personally quite like having the language protect me from making silly mistakes, which is why I use typ

Having type checking is indeed a matter of preference. I personally quite like having the language protect me from making silly mistakes, which is why I use type declarations liberally in my Common Lisp code. With SBCL doing its best to ensure they hold it has probably saved me minutes of headaches each project. Also CL is very pragmatic and nobody bats an eye at, for example, woo being based on a C library.