From my current location, it's a 13ms round-trip to the nearest Google server via a good fixed broadband connection; over 4G, that would be ~63ms because of the latency overhead of the cellular connection. That's a substantial difference for a lot of real-time applications.
I do not deny that 4G has worse latency, but 5G will not provide sub millisecond round trip latency for regular internet based applications. Sub millisecond latencies are due to local communication which can replace DSRC/802.11p in car2car communication and similar applications.
