Your example is only for dumping memory.
> this is a weak argument for what computers should do; if LE is more efficient for machines then let them use it
Computers really don't care. Literally. Same number of gates either way. But for everything besides dumping it makes sense that the least significant byte and the least significant bit are numbered starting from zero. It makes intuitive mathematical sense.
Not only dumping, but yes I agree it only matters when humans are in the loop. My most annoying encounters with endianness was when writing and debugging assembly, and I assure you dumping memory was not the only pain point.
> Computers really don't care. Literally. Same number of gates either way.
Eh. That depends; the computer architectures used to be way weirder than what we have today. IBM 1401 used variable-length BCDs (written in big-endian); its version of BCDIC literally used numbers from 1 to 9 as digits "1" to "9" (number 0 was blank/space, and number 10 would print as "0"). So its ADD etc. instructions took pointers to the last digits of numbers added, and worked backwards; in fact, pretty much all of indexing on that machine moved backwards: MOV also worked from higher addresses down to lower ones, and so on.
Same number of gates either way
Definitely not, which is why many 8-bit CPUs are LE. Carries propagate upwards, and incrementers are cheaper than a length-dependent subtraction.