In this specific case it's more of a nitpick, I think. Even shellcheck won't demand double-quoting `$#` because everyone(?) knows that it'll always be a number

In this specific case it's more of a nitpick, I think. Even shellcheck won't demand double-quoting `$#` because everyone(?) knows that it'll always be a number and have no whitespace in it nor evaluate to an empty string.