Just a Bit - implicit conversions and the BIT datatype

Consider the following:

DECLARE @I int;
DECLARE @B bit;
DECLARE @False bit;
DECLARE @True bit;


SET @False = 'false';
SET @True = 'true';
SET @I = -5;

--this much we pretty much expect
select @False, @True

-- but what about this ?
WHILE @I < 5
BEGIN
SET @B = @I;
SELECT @I
, @b;
SET @I = @I + 1;
END

While the BIT datatype will throw errors