For most consumers, 4K and 8K TVs are unlikely to provide an actual experience boost, despite the denser pixel count. The reason is that the human eye cannot tell the difference between 4K and 8K from 1080p unless a person sits uncomfortably close to a screen, or unless the screen is really huge. Simply put, 4K is a waste of money, as 8K will be, for most people.
Most people simply do not sit close enough to the screen to perceive the difference 4K or 8K can provide.
It is obvious why consumer electronics companies want to sell you new TVs. TVs no longer break, and manufacturers need new reasons for you to buy a new screen and move the existing screen to a bedroom or elsewhere in a house.
Content developers have their own reasons for wanting higher resolution: it is part of the decades-long effort to create greater realism and experiential immersion.
The trend to bigger screens therefore makes sense. Either people have to move closer to their screens, or screens have to get much bigger. Bigger screens probably are the only realistic option.
But 4K and 8K really make sense for business, medical, industrial and other applications where a human operator actually is very close to a screen with very-rich detail.