Solved! Why big smartphone chins, but no buttons?

[Fluen_]

So I noticed, that my friend Huawei device has a gigantic chin, but no buttons.
I compared his phone with my Samsung j5 2017, which has buttons, and his actually had a bigger chin.

What is the reason that they have such a big chin, but no physical buttons?

 

[hang-the-9]

There may be touch buttons there, or that is just how they designed it, could be to use a certain screen size, could be to keep the size to hold the electronics.