The quality of comments on are are further proof of how far downhill
Ironically, this is exactly what your post made me think. It's 2014 and someone on Slashdot is asking what the performance and security considerations of virtualization are? Really? Every one of your questions is answered within about 30 seconds of Googling and reading.
that exist purely for style
They exist so that the software keyboard can move out of the way and the input mechanism can be changed by software. It's a trade off. You trade the ability to type more quickly for a per application, software defined user interface.
(consumption and feeding you ads)
You forgot communication. Phone calls, email, text messages, facebook, WhatsApp, Instagram, Snapchat, Yik Yak (I could go on for a while).
An authority is a person who can tell you more about something than you really care to know.