Let's be honest: The average user doesn't expect anything at all to do with CRX files or extension updates. They just expect an extension to install when they click install, and to work from then on.
I have a button on my website that says "Install extension." I don't tell them it's a link to a .CRX file; that's an implementation detail. If you asked any of my users whether they had downloaded a file (let alone what its extension is), most couldn't tell you. Similarly, the Chrome Web Store has buttons that say "Add to Chrome," not "Download Trusted .CRX File."