Quantum Superposition is a thing that exists in quantum mechanics. It's like a mix of states, but not really. It's like being in two places at once, but also not really.
You want to know why it's useful? Well, it's not. But, it's also kind of useful. It's like, imagine you're a particle, and you're in two places at once. It's like you're in New York and Los Angeles at the same time! But, also not really.
Want to learn more? Check out:
Quantum Superposition In Action
Or, if you're feeling extra adventurous:
Quantum Superposition In The Real World (But Not Really)
Or, if you just want to give up: