It's a bad connector design that's much more prone to breakage than it's predecessor, dropped necessary pin layouts, has the worst cable design I could think of that is virtually guaranteed to die within a year, didn't lay out it's electrical connectivity correctly so it will have to have a silent refresh this year (the pin design on the iPad Pro is different...), had terrible controllers that necessitated in cable chipsets that massively increased costs, and is part of the Made for iPhone programme of rentseeking.
It also has the dubious honour during it's introduction of only being licensed under MFI if you committed not to raise it on a dock, even though Apple's own MFI case design spec specifically said that had to happen to be compatible with their own cases, and no-one at Apple fixed this for nearly two years.