Either there's info missing from MR's article, or the explanation doesn't entirely hold water. Partially, yes. Completely, no. If it just about the security, then Touch ID shouldn't work after the repair. Again, according to the article, that's not the case. Touch ID does work using the replacement home buttons. The error-53 message only appears after an update to the latest version of iOS. If that is indeed the case, the security isn't secure and it sort of nullifies the reasoning of avoiding security compromises.
In my mind, if it's about security, the replacement home button would cease to work immediately. That's security. Requiring an update to trigger the Error-53 really isn't. Fairly, there's most likely a lot I'm missing, but if the article is correct, Error-53 doesn't prevent installing unapproved Touch ID sensors; hacked or otherwise.