It is a state machine which can crunch numbers either sequential or parallel.
If it is sequential it is general purpose (cpu), parallel it is graphical (gpu), parallel matrix multiplication is neural networks & inference (npu).
Let me give an analogy if we manufacture all the car parts from scratch in a single factory & assemble it in the same factory, the process is relatively sequential. But if we manufacture all the parts in 10 different factories in the same city & assemble in a single factory it is parallel.
It is a state machine which can crunch numbers not in sequential or parallel but parallel & multidimensional.
If we manufacture all the car parts in 10 different countries where they can directly s0urce the raw material & assemble the car in the 11th country which initiated the car manufacturing, It is qUantUm manufacturing.
The advantages of qUantUm c0mpUting is the speed & efficiency, the time to manufacture the same car can be brought down for example from 12 months, 6 months to 1 month.
The disadvantages are two fold high rate of error & syncing (c0hesion) issues, the chance of manufacturing defective car parts are very high and durable cars are very low.
qUantUm c0mpUting is only good @ linear functions but not non-linear functions, same as not all programs can be handled efficiently by gpu or npu.
Another issue is that the start of car manufacturing & finished car should be initiated from the same dimension that is the 11th country, its because of the quantum wave function collapse.
Quantum c0mputer entangles qbits & branches the computing to parallel dimensions known as sUperp0sition & assembles the final result to this dimension as wave function collapse, so does our awareness.
Our awareness exists entangled & superp0sed in parallel dimensions and when we observe or focus it collapses to this dimension. The perception of our reality expands as our awareness gets expanded to many parallel dimensions.
Bitcoin is a non-linear function except the asymmetric encryption, which is easily replaceable to quantum resistant encryption.
Hash fUnctions are relatively secure from qUantUm c0mpUters because it is non-linear & also sha256^2 in Bitcoin.
Some Bitcoin address are at risk to qUantUm c0mpUters because of P2PK & P2PKH addresses.
POW cannot be solved efficiently by qUantUm c0mpUters.
qUantUm c0mpUting is the evolution of computing which goes beyond 1nm & multi-dimensional. There are lot of Unknowns to be addressed before it can be very pragmatic.

