Yeah, marketers loves to say that because there is a latency gain for the wireless part of the request travel. The more the information you request is close to the antenna, the more you’ll benefit of this improvement. However in real (actual) condition a request travel hundreds or thousands of kilometers through many nodes, each one adding up a bit of latency. So in the end you may feel a difference if you use VR in SF or make HST in central London. You won’t notice the gain if you’re trying to load a page hosted far away from you.
In fact latency is way more impacted by the web neutrality but that’s another subject.
If you live in a major city close to the target datacenter, maybe. I have an excellent last mile (500 Mbps symmetrical FTTH) and pings to sites like google.com still go above 300 ms. 5G wouldn't help me at all, probably the opposite. The vast majority of that time is spent in data bouncing around the world through very inefficient routes.
In fact latency is way more impacted by the web neutrality but that’s another subject.