So performance would increase since hashing is faster than binary-searching.

However, the problem of collisions across threads and dealing with concurrent map key insertions still remains. e.g. when two different cities produce the same hash (one at each thread), how can we atomically compare 100 byte city strings and correctly do collision-solving (using linear probe, for example - https://nosferalatu.com/SimpleGPUHashTable.html)

Atomic operations are limited to 32-bits.