Languages - yes, all the other links - almost never.

Given the image on the blog post, I thought it didn't include the languages, but looking into the wiki page about the change, it does include the language bar as well.

Damn. I use that all the time. Wikipedia is one of my favourite dictionaries.

I use it for the same thing. This allows me to learn what specific word is used for [obscure thing] in a different language. Eg computer hardware related words for my native language.

Yes! I found Wikipedia article names are fairly reliable as a translation reference, especially for technical terminology. In my language, translations of technical terms in Wikipedia article names are often more accurate than the vast majority of random blog posts and articles on the web, and occasionally even better than some technical dictionaries, which may use old-fashioned or outdated terms.

This has also been my only use of the sidebar. It looks like the new design takes this into account and moves the language selection to a more prominent location at the top right next to the title.