"Good enough" does not mean anything in itself. Good enough for what?
More and more of the use cases move away from providing higher data rates to smartphones, so yes, oone could argue that 4G is currently good enough for that specific use case, but that's just one among many.
5G is about supporting greater capacity in general (so maybe the same rate as 4G but to more users at the same time, which is important in dense areas), massive IOT, extremely short latency, high reliability. These are important use cases but they are mostly off the radar of the average person.
I've yet to read a compelling argument in favor of large-scale 5G deployment, and I'm far from being anti-tech. Except for self-driving cars, I suppose.
Latency benefits would enable many new realtime applications both in business and consumer end and speed up many existing ones so they'd be much less janky to use, and thus more accessible to people.
It's impossible to see all the future exploits the new technology allows. All the things we do are built upon other existing ideas, moving to higher speed, lower latency connection is another step in progress.
Think about being able to download several GiB application on the fly just to view a demo for a house, or get the schematics for what you're viewing in realtime with AR
There's a reason China is so keen on it (let's not get on the state surveillence bandwagon yet). Their population and population density is consistently high in so many cities, that they face contention problems more than anyone else. If we're talking relatively sparse cities found in many places around the world, then no, the extra local capacity is probably not in high demand.
I would bet that 5G has cut down base stations which operate similarly to 4G, but the option to not use a new generation only works for maybe 1 generation before it gets too far behind. Data consumption is still going up after all, and some countries (such as Australia) have already mandated the shutdown of older generations, with 2G switched off to refarm spectrum, and 3G scheduled for switch off.
Attention is highly latency sensitive, and bringing reaction for your action a second sooner has major implications, and significantly increases your ability to interact with and understand content
More and more of the use cases move away from providing higher data rates to smartphones, so yes, oone could argue that 4G is currently good enough for that specific use case, but that's just one among many.
5G is about supporting greater capacity in general (so maybe the same rate as 4G but to more users at the same time, which is important in dense areas), massive IOT, extremely short latency, high reliability. These are important use cases but they are mostly off the radar of the average person.