They are both "wrong" compared to big-endian, but M/D/Y is by far the least logical of the three formats.
M/D/Y should never be a default for any software without the user explicitly selecting it or specifying their country.
M/D/Y should never be a default for any software without the user explicitly selecting it or specifying their country.
M/D/Y seems to be the most practical because it reflects how dates are spoken in American English. It separates the date (month/day) from the year, which in many cases can be omitted, while also keeping the larger unit, the month, up front.
The majority of English speakers and people in general don't speak American English, so it makes zero sense to default to "M/D/Y", unless the user explicitly states to use American English, over a more logical order, ideally Y-M-D.
Pretty much all defence in this thread of M/D/Y is just American exceptionalism.
As for practicality, I don't think closely mirroring English grammar makes it any more practical for written communication.