There are a lot of advantages though if you can get the interpreter fast enough to write more the standard library in Python instead of C. Racket moved to the C

There are a lot of advantages though if you can get the interpreter fast enough to write more the standard library in Python instead of C. Racket moved to the Chez Scheme VM recently because it is much easier to maintain Racket/Scheme code than it is to maintain C. At my job, there are way more code scanning and audit requirements for any serialization code written in C/C++. While serialization code is always somewhat risky, at least you don't need to worry about buffer overflows in your parser if it's written in Python.