Then one day you come back and resize the array to a multiple of the memory alignment, and BAM! Off-by-one errors, or even vulnerabilities. Or you enable more

Then one day you come back and resize the array to a multiple of the memory alignment, and BAM! Off-by-one errors, or even vulnerabilities. Or you enable more strict build settings and BAM! You have to go back and deal with all the places your code allows you to write off the end of a buffer because you just didn't give a damn before.