When you specify the capabilities of telecom network equipment and write technical specifications and standards for those networks you create scenarios called "use cases." In 5G, this process of envisioning scenarios for how the network could be used includes things that are, to put it kindly, speculative.
Here are just some of the unlikely futures embodied in 5G use cases:
5G is a critical enabling technology for autonomous vehicles
5G is going to transform factories
5G IoT devices will be everywhere
Telemedicine is enabled by the 5G generational transition in mobile technology
Telcos will be in the business of providing network cache and computing resources
Many people will be walking around with virtual reality (VR) or augmented reality (AR) headgear on
Use cases or edge cases?
Let's start with autonomous vehicles or "self-driving" cars: This is a typical "use case" that looks good if you assume the roads can be blanketed with both 5G radios and very low-latency 5G networks and network nodes. The fact is that makers of autonomous cars cannot rely on any mobile network connectivity at all, and can even less rely on or wait for pervasive low-latency 5G networks that implement features like network slicing to isolate vehicle to vehicle traffic on a dedicated set of network resources. Autonomous cars, and vehicle to vehicle (V2V) communications, are going to happen with or without 5G.
Factories and telemedicine, similarly, could use 5G radio technology, but why would they? Why would a telemedicine application make use of wireless connections when a wired connection is available? Why would a factory use wireless to gain a small increment in flexibility when moving and reprogramming factory machines makes up the vast majority of the cost of reconfiguring a production line. If you sense a bit of déjà vu, it is because telemedicine was trotted out as a key use case for 3G and 4G, and it still isn't.
One of the most speculative use cases in 5G hype is augmented reality (AR) and virtual reality (VR). Imagine tens of millions of AR users walking around with headgear on, relying on low latency processing inside the mobile network to keep their headgear light and inexpensive, and to prevent the motion sickness that comes from the feeling that one's vision doesn't quite correspond to one's movement. This requires "edge computing."
AR and VR are both nascent technologies. They are unlikely to be either enabled or blocked by the pace of 5G deployment. It is also an open question whether they are going to break out of niche applications.
Edge computing and 5G
The theory behind "edge computing" in 5G is that applications will have to be pushed out into the mobile network operators' networks to satisfy latency requirements, and that network operators will develop a huge business in assuring that applications like AR, and media like Netflix shows, get to users' phones in the optimal way.
Mobile network operators do not have the expertise that Google, Amazon, Apple, and Microsoft have in operating flexible computing resources. The implication that 5G will turn mobile network operators into the new platform for content delivery and software-as-a-service is unlikely to happen.
Even optimal scenarios have flaws
Even some of the sensible targets for 5G small cell deployment are seeing millimeter wave technology come up short. An article in Ars Technica in October 2019 described deployments in football stadiums and basketball arenas as providing only incomplete coverage of seats in those venues.
Seeing the world through telecom-colored glasses is not new. When 3G was launched, all sorts of fanciful scenarios were part of the public relations push, to promote the idea that 3G capabilities were transformational. But Steve Jobs and the iPhone prevailed in shaping the role of 3G: The mobile experience is the internet experience, and the role of network operators is to deliver the bits and get out of the way. So it will be with 5G.
Are fantasies about 5G pernicious, though? That's the Bad Part of 5G.