Why is $2\text{'}$s complement so useful?

Choice $1$ of $4$: the same addition operation for unsigned n$-$bit values also yields correct outcomes when interpreted as n$-$bit $2\text{'}$s complement values $($assuming the operation's output can be represented in the given number system$)$

Choice $2$ of $4$: positive values in n$-$bit two's complement are equivalent to n$-$bit unsigned values

Choice $3$ of $4$: It allows one to represent negative, whole numbers in binary

Choice $4$ of $4$: It provides a unique representation of zero