They aren’t, or they are, but not to all things.
If you took a normal computer and a quantum computer and run normal programs on it, would the normal computer properly be at least as fast.
Quantum computers are only faster for tasks that uses the q-bit functionality.
If you take a labyrinth and asked a normal computer to solve it, would the computer have to test each and every path one at a time. A quantum com computer could test several paths at once, all dependent on the numbers of q-bits.
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