NISQ devices cannot be simulated by brute force using the most powerful currently existing supercomputers.
NISQ will be an interesting tool for exploring physics. It might also have useful applications. But we're not sure about that.
NISQ will not change the world by itself. Rather it is a step toward more powerful quantum technologies of the future.
Potentially transformative scalable quantum computers may still be decades away. We're not sure how long it will take.
The number of qubits is an important metric, but it is not the only thing that matters. The quality of the qubits, and of the "quantum gates" that process the qubits, is also very important. All quantum gates today are noisy, but some are better than
others. Qubit measurements are also noisy.
For today's best hardware (superconducting circuits or trapped ions), the probability of error per (two-qubit) gate is about 1 per 1000, and the probability of error per measurement is about 1 per 100 (or better for trapped ions). We don't yet know whether systems with many qubits will perform that well.