Speaking as a software engineer, this does not make sense from a security standpoint, and Apple'simply logic here is flawed. I could understand if Apple selectively disabled the Touch ID feature when this check fails, but to completely brick the entire phone? There's absolutely no need to take it to that level.
Apple doesn't have official repair channels that are easily available in all countries. Furthermore, the repair channels Apple does offer are often so outrageously expensive that most independent shops can do it significantly cheaper. Apple knows this, and this is an obvious and desperate ploy to drum up more business for their own repair channels. If you've seen the repair price for an iphone recently, it has gone up dramatically in the last few years, and there's just no excuse for it to be so high, especially since they use such cheap components (16GB storage in the year 2016 anyone? ).
Apple possesses the capability to selectively disable touch ID. The fact that they completely brick phones in this case, without warning, tells me they haven't really thought it through.