https://www.cnet.com/news/five-phone-cameras-three-even-phone-makers-cant-decide-whats-best/

The megapixel one-upmanship war is largely over now -- in large part because people have realized that more megapixels doesn't automatically equate to a better camera and better pictures. But the mobile industry, being the competitive market it is, the battleground has shifted, and this time it's all about how many lenses you can fit on one phone.

As with many trends in the mobile world, we can look to Apple for popularizing the idea of having more than one camera on the rear of a phone when it unveiled the iPhone 7 Plus back in September 2016. Since then we've seen increasingly more cameras on phones, and it's hard to know where all this madness might stop.