Question about Elisp packages

Hello, Xemacs gurus! Amir Katz referred me to this list when I asked him a question. I am the maintainer of Mailcrypt, which is struggling to work correctly on Xemacs (I use FSF Emacs *blush*). If anyone can answer my question, please CC me since I don't subscribe to this list. The question is: should elisp packages be compiled with the "--vanilla" option (or "-q -no-site-file" for older Xemacs)? Is there a traditional answer? Are there compelling arguments either way? The original mailcrypt does not turn off site customization, and I don't have any to turn off. However, Amir suggested that I use the "--vanilla" option. Any suggestions? Thanks in advance, Len.