Recently, Huawei came up with an announcement saying that the manufacturer is working to make all-screen fingerprint authentication co-exist with in-display selfie cameras and expects it to be ready in a year or two.
If the all-screen fingerprint authentification works as expected, users will be able to touch anywhere on the display to unlock the phone or certain apps. Anyhow, for both all-screen fingerprint authentification and in-display cameras to co-exist, the manufacturer would have to place a lot of sensors underneath the display, which calls for a significant increase in cost.
If you care for your battery life, you have the alternative to switch off some sensors in some parts of the display. For that matter, Huawei would use Machine Learning technology in order to make sure the power is directed to those parts of the screen you touch.
We shall see if the costs of implementing this could be efficient for mass-production. However, by now, different brands are working on in-display selfie camera technology, so we can say this might become a trend in smartphones.