It’s faster than network data transfer. I don’t know exactly how fast can WiFi go, but most if the time it can’t even exceed 1Gbps. However, USB-C 4 V2 can reach 80 Gbps, and isn’t all that affected by electromagnetic interference.
For transfering a few photos, you won’t notice a difference. But if you need to back up a 256 GB phone, the difference in speed is actually big.