One of the areas I've heard should be improving with 5G is latency. On 4G we're talking O(10ms)? which on 5G, so says the marketing, should be O(1ms). If this is true, it will make a noticeable impact on the responsiveness of web driven apps (aka almost all apps) as well as video/audio chat liveness. Was this oversold to me (highly probable)?
Beyond URLLC are protocols aimed at replacing wires in "serious" industrial control systems: things like real time control of grid switchgear and heavy machinery, so you might not see it on your phone. Latencies of the order of microseconds have been demonstrated in recent years and the stretch goal is about 200ns.
In addition to mobile network latency you have to add a few more things - depending on how far you are from the data centre serving the web app you're looking at ~20ms-300ms additional network latency, plus however long the server takes to process your request, regardless of 4G or 5G. Check out https://www.cloudping.info/ for some ping times to AWS datacentres around the world
https://i.imgur.com/Dg4Jit5.png
That's my RTT ping to 8.8.8.8 as I travelled south on CalTrain from SF last week, on T~mobile's network.
Now, this is on an old phone that is only capable of HSPA+. However, the actual performance on the whole is still nowhere near any theoretical limits, or even limits of HSPA+.
For example: A 10ms video refresh rate would be 100fps.. the average movie is 24fps.
But in general for web browsing, 100ms would be unnoticeable yeah.