I work in electronics manufacturing and I'm torn on this issue.
On the one hand, fuck Apple for requiring to go through so many hoops.
On the other hand, every device my company makes has an internal checksum and if one PCB is installed incorrectly, the main board throws a fit because the device checksum doesn't match.
It sounds like Apple may do something similar for their products and it sort of makes sense: determined people try something crazy like take an older iPhone and install a newer Wireless module or replace Lightning with USB-C. Neither of those things were intended by Apple, and there's a huge potential that it wouldn't work.
With that said, it's absolutely overkill for things like display or digitizer replacements, which are going to be the majority of repairs on iPhones.
Tl;Dr - fuck Apple, this is dumb, the users have the right to repair