Comment by DonaldFisk

The problem with Lisp is that there are different dialects, and if you program in more than one, you need to be aware of the differences between them. It would be nice to be able to switch between them on different projects without being caught out by their differences before getting used to the other dialect, or having to context-switch. It would also be nice to port programs from one dialect to another without major editing. But Picolisp is another dialect, which on the surface is quite different from Common Lisp and Scheme/Racket and, I assume, Clojure. If you want to keep your Lisp implementation small, why not just implement a subset of Common Lisp, or build/use a Scheme variant?