1. Save space
Yes, removing the touch buttons below the display does create more space, or helps save it for other components. It also allows to make the bottom chin much slimmer than what it’d be like with a row of physical buttons beneath. So, in short, you get a bigger display in the same footprint, thus higher screen-to-body ratio.
2. Prevent unwanted touches
Obviously, if you remove the physical touch buttons at the bottom of the phone, you can’t inadvertently press any. Thus you don’t risk of closing an app when you rotate your phone to watch videos or other situations where that may occur.
3. Easier to use
According to Cubot, virtual keys are easier to use than physical ones. That’s because real buttons need pressure of some kind, meanwhile virtual ones get activated by the slightest of touch, just like any part of the display. It’s probably also easier to reach as they’re on the display you’re already tapping on.