The gaming scene is changing (evolving?). No more is it limited to gamepads and keyboard-mouse configurations. Touch-based games, hate it or love it, is now a big part of gaming, maybe even bigger than your orthodox forms of gaming (consoles, PC). Call it ‘casual’ gaming if you’re a PC/Console nazi, but you’ll have to agree, touch based games are serious business now. Many have come to despise or simply discard touch-gaming altogether, because of reasons such as “its not what gaming is” and “only the thick/shallow enjoy touch”.
That being said, I do very much enjoy old, turn-based RPG's on touchscreens. Final Fantasy 3 is a great example of games that work extremely well on touch devices.
of course for touch only devices it works well for simple experiences
If, however, it is added to a controller with real physical buttons like the PS4 is believed to have, then it can provide significant advantages. The power of touch-screens is their programmable nature. Devs can do whatever they want with them, adding new ways to control certain elements of the game or simply more buttons.