01 · Memory

Registers

n bits hold one of 2ⁿ strings. n qubits hold 2ⁿ amplitudes at once — and still give you one string when you measure. That is the whole resource.

In English

Three classical bits store one number from 0 to 7. Three qubits store eight amplitudes at once — a weight on every number — and still only give you one number when you measure. The extra is in the weights, not in extra answers.

Try this: Flip classical bits. Then put the quantum register in superposition and read the bar for each basis string.
Keep this: n qubits: 2ⁿ amplitudes, one measured string. That is the resource.

Lab · n bits vs n qubits

Classical · one string

|00⟩
1100%
|10⟩
00%
|01⟩
00%
|11⟩
00%

Quantum · 4 amplitudes live

|00⟩
0.525%
|10⟩
0.525%
|01⟩
0.525%
|11⟩
0.525%

The exponential is in the description, not in the readout. n qubits are a 2ⁿ-dimensional complex vector. A measurement still returns n bits. If you needed all 2ⁿ answers, you would still need 2ⁿ shots — and you would have wrecked the interference.

Algorithms win when they steer amplitude into one (or a few) kets you actually want to read. That is Grover, Deutsch, and Shor. It is not “try every input at once.”