Xiaomi 5 also appeared this function in the development version. However, when Xiaomi applies this function, it is a bit like Apple. Xiaomi's operating principle is to touch back to the previous level and double-click the home button to quickly switch programs. This operation will reduce the life of the home button, so not many people use it.
In the official version, the logic of Xiaomi's touch on the home button is changed to direct touch to return to the desktop. Because Xiaomi has three donkey kong keys of Android, there is no need to add a function to attack the next level at the risk of infringing others' patents.
Moreover, Xiaomi VI's home button cannot be pressed, even if it supports the function of touching back to the next level, it is not practical. It is better to return to the desktop directly with the ordinary home button.
In contrast, Huawei uses virtual buttons. There are no left and right function keys and enter keys, so Huawei adopted the design of touching back to the next level.
For Xiaomi, this design is completely unnecessary. Because of the enter key, it will be more complicated to change the middle to the enter key.