The bits are not redundant. When you have a larger alphabet, you get more possibilities for the same length of password. Sure you could also have a password that consists only of 1 and 0, but then you would have an unreasonably long password. Just as you would also have for a hex password, to a lesser degree. To carry it to an extreme you could have your password consist of just one character repeated a secret number of times, and yeah, sure, in your little theory world the amount of entropy could still be the same, but practically speaking it's a stupid idea, just like using hex characters.

You really are confused about this stuff.

You also seem completely unaware that many sites have password rules that require special characters that don't exist in your scheme... lol!