[racket] c extensions and embedding

In the documentation, would it be a good idea to discourage the use of C 
extensions and embedding of Racket (in the old Inside MzScheme senses of 
"extension" and "embedding")?

I have been discouraging their use for a few years now.  I think they 
made more sense when mzscheme was smaller, was slower, used the CGC, and 
did not have an FFI.  Today, extensions and embedding seem like a last 
resort, when one has ruled out all other approaches.

This seems like one of those things that is likely to derail potential 
new Racket adopters: they pick a poor approach that initially (according 
to documentation) seems viable, they run into difficulty, and they might 
give up on the entire platform.

Or, if extensions and/or embedding work better today than I thought they 
do, then my mistake, and I withdraw the suggestion.

Neil V.