Hi wolly
JoomlArt.com is an English-only website, so there's no need for JA Multilingual to be used there. Since the site doesn’t offer content in multiple languages, a multilingual extension wouldn’t be relevant.
If the question was implying that JoomlArt doesn’t trust its own product, the reality is simply that JA Multilingual is designed for sites that need multiple languages, which doesn’t apply to JoomlArt.com.
Let me know if you need help clarifying this further!