HTC's experiment with a dual rear camera setup on the M8 might not have proven as (commercially) beneficial to the company as its bossed may have expected, but the experiment opened doors to an all new arrangement of imaging sensors which was later adopted by many other companies. Quite a few phones ship with dual rear cameras, but to say that they can't be done without would be going too far ahead of ourselves.
Samsung has been rather innovative in the recent years, especially with its edge screens. From what we're hearing, Samsung, along with arch-rivals Apple might soon ship phones with dual rear cameras — that is, if the their tests which are said to be underway bear fruit.
Dual rear cameras allow for a new degree of sensing to be introduced to imaging. HTC, for example, used the second camera to calculate depth which allowed for a myriad of customization features on the M8, especially ones which dealt with depth-of-field.
