Either P=NP or not. Hoping one way or the other changes nothing. Nor does it change how efficient computing is, nor does it have any effect on cryptography. Discovering a vastly more efficient means of factoring primes--perhaps via quantum computing--would do that. But just learning that P=NP does nothing to further such a discovery. Almost certainly, if P=NP, the exponents and/or constants in a polynomial factoring algorithm would be galactic. (FWIW, Knuth believes that P=NP and that it has no practical consequences.)

Why? Nature doesn't care if people are making financial transactions based on flawed cryptography.

Not really. P=NP but the degree of the polynomial is Grahams number doesn't let people into your bank account

it could make lots of compute way more efficient, not sure why it is catastrophe..