... not a quantum computing expert yet, just getting a first important clue.
while single bit can be in either 0 or 1 state, qubit (quantum bit) can be in the superposition of two 0-1 states, therefore can hold 4 possible states.
2 bits can hold 22 = 4 possible states, 3 bits: 23 = 8, 4 bits: 24 = 16, ..., 1000 bits: 21000 possible states, ..., n bits: 2n possible states.
2 qubits can hold 24 = 16 possible states, 3 qubits: 26 = 64 possible states, 4 qubits: 28 = 256 possible states, ..., 1000 qubits: 22000 possible states, ..., n qubits: 22n possible states.
2n is much smaller than 22n quickly ... as n increases.
not only the state-capacity is an improvement, because there are / will be quantum gates (some are already done, other in development still) that operate on qubits, more assembler mnemonics, more ways to optimize software on low-level.
i imagine that there will be quantum assembler letting programmer take advantage of these quantum gates (more of the fast processor operations available), compilers will take advantage of that as well.
sooner or later we'll be seeing quantum assembler inserts in high level code as well.
my ambition is to include low-level mnemonics of quantum assembler in 'Ola AH' Programming Language, in form of quantum assembler inserts to allow to optimize manually code parts.