4K resolution on mobile devices is currently a significant advancement in the global mobile industry. Since Sony introduced the first Xperia 4K smartphone, it has sparked debates within the tech community about whether 4K technology on phones is truly essential.
What is 4K Resolution?
4K resolution (Ultra HD) is a screen concept with dimensions of 3840 x 2160 pixels, providing four times the resolution of Full HD (1920 x 1080 pixels).

4K Resolution
On the small screen of a phone, the significantly higher pixel density of 4K compared to Full HD makes it very difficult for the human eye to discern. The pixels and details are too small for normal human vision at typical viewing distances. Therefore, the difference between Full HD and 4K on the same 5.5-inch mobile device is negligible.
The Benefits of 4K Resolution on Phones for Users
1. Ideal screen resolution for those who frequently experience virtual reality (VR) applications

Virtual Reality (VR) Technology
One of the significant reasons why 4K resolution on mobile phones benefits users is Virtual Reality (VR) technology. With high resolution, images achieve very sharp clarity.
2. Watching movies in 4K quality

Watching movies in 4K quality
Currently, YouTube and Netflix are two applications with some 4K entertainment content, offering high-quality movies and videos for users, enhancing their entertainment experience.
Limitations of 4K resolution on smartphones
Battery drainage issues

High-resolution screens drain battery quickly
Having a large pixel-dense display tends to put more strain on your phone's CPU, significantly impacting battery life. Imagine a 4K smartphone draining its battery rapidly while you're indulging in entertainment like watching movies, taking photos, or gaming.
With a 4K display, don't expect much of a difference.

The disparity between screens isn't significant.
With a 5.5-inch display, users can easily discern the difference between Full HD and HD. However, comparing Full HD to 4K is an entirely different story. Even experts find it challenging to differentiate between them, especially on mobile devices with mere 5.5-inch screens.
In conclusion
So the answer is clear, us users may not necessarily need a 4K screen on our phones. However, phone manufacturers like Xiaomi, Samsung,... have different priorities. They aim for numbers larger than 2K, such as Xiaomi 12 Pro 5G 256GB, to market their products, surpass competitors, boost brand marketing, and facilitate easier sales.