Me neither, but I also wonder how many non-expert users actually know that it is available. There is the initial dialog about Siri when setting up a Mac. After that, it is not that prominent. Moreover, it's a bit embarrassing to use in an office environment anyway.
That reminds me: I knew some people who had been using Macs for years who did not really know that Spotlight existed, let alone that you could use Command + space to start a Spotlight search. They would launch applications through the Finder and put regularly-used applications in the Dock.
