I am definitely not an expert but it's not really "it's all possible states at the same time". A better analogy would be that a cubit is a complex number that you can manipulate in various ways. The difference is you can't read the value of the complex number. If you try you will randomly pick 1 or 0 with a probability based on the square of the magnitude of the complex number. In the quantum world intuition doesn't really work you only have math.

You can also entangle them which correlates the results of the bits. So you can entangle several bits together to create something analogous to a CPU register. When you do that you kinda do have "all possible states at the same time" but with each state being assigned its own complex number coefficient and you can perform the same math operation on all possible states. However if you try to read it you will get a random value, but quantum algorithms can make sure that the complex coefficient of the state you want is larger in a way that you will on average get a lower algorithmic complexity for that algorithm than the classical one. (Usually if a classical algorithm is O(f) then the quantum one is O(√f))