Emergency priority been in every mobile system since AMPS.

5G has a few use cases. In very high user density areas, such as stadiums, it's possible to have a huge number of short range connections in the 24-40GHz band. This allows people at the game to watch the game on their phones. Many major stadiums installed this back in 2020.

If you want huge bandwidth, you're going to need near line of sight to the base station. The high band won't go through much. Stadiums and entertainment venues are the ideal case, because they're designed to let a large number of people have line of sight to something. So they were done first.

Worst case is a subway or complex building interior. Samsung has little brick-sized beam-forming units.[1] It takes a base station every 150-200m or so to provide good coverage in the high bands. AT&T is integrating them into street lights.[2] Not clear how they backhaul.

[1] https://www.samsung.com/global/business/networks/products/ra...

[2] https://5ginsider.com/carriers/att-rolling-out-5g-powered-st...