That's not the point. Contrary to any other LTE phone on the planet, you cannot use LTE on the iPhone, even if the other carrier's network uses the same bands and is (would be!) technically 100% compatible.
Apple advertises their phones quite verbosely on their web site:
"Cellular and Wireless:
GSM model A1428*: UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz); GSM/EDGE (850, 900, 1800, 1900 MHz); LTE (Bands 4 and 17)
CDMA model A1429*: CDMA EV-DO Rev. A and Rev. B (800, 1900, 2100 MHz); UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz); GSM/EDGE (850, 900, 1800, 1900 MHz); LTE (Bands 1, 3, 5, 13, 25)
GSM model A1429*: UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz); GSM/EDGE (850, 900, 1800, 1900 MHz); LTE (Bands 1, 3, 5)"
http://www.apple.com/iphone/specs.html
But what are these claims really worth? I can have a contract with a carrier that operates a perfectly standard-conforming LTE network (LTE is not just some hodge-podge cobbled together individually by every carrier - it's a worldwide defined standard, you know?) on band 3. Like, for instance Swiss Swisscom. And the iPhone - contrary to any other conforming headset on the market - is still doing
nothing on that network.
That means Apple's claims regarding LTE are basically worth...
nothing.
So what purpose do they serve? They look like
deceptive advertising, designed to trick me into assuming I can get LTE - when, in reality, I can't. And why can't I? Because Apple has knowingly and arbitrarily disabled the functionality in software.