normal computer have to try every combination one at a time (or per number of cores).
Quantum computer can try all of them at once.
It’s very useful if you have a lot of combinations to try, like trying what molecule works best as a treatment for X.
It isnt very useful in task, like if X then Y. Or keep track of Z.
So basically, it wouldn’t enhance your smartphone in any other way, but in use cases where you have lot of combinations, it’s light years ahead of any other computer