Factoring 2048 RSA integers in 177 days with 13436 qubits and a multimode memory
One day you can start calculating private keys based on public keys.This is the biggest crypto puzzle: find private key of Sathoshi Bitcoin wallet with 1 mln bitcoins. Over $50 Bln prize for one crypto puzzle.This would be AlphaGo moment of quantum computing if you could make that one attack successful even while paying huge price (e.g. years of quantum datacenter work).