Off course, the most fun is the building proces and not the using of such projects. But keep in mind if all the effort is paying off in every usage.
So you have to walk to the kitchen, grab a cup. Put it under the coffeemachine. Take your phone, unlock it. start pimatic, scroll to the appropriate buttons. Push on a button just to see the magic of brewing coffee by the machine in front of you. You could have done exactly the same with the physical byttons on the machine it self.
But such a hack could provide you some time programmed cup of coffee when you put a empty cup under the machine before you go to bed.
In short what you need (how I would approach it):
Use a ESP8266, make sure it has always power even when the machine is off (but plugged in)
Find what to connections are closed when pushing the desired buttons.
Solder 2 wires to the connections
Put a relay between the 2 wires
hook up the relay to the ESP
Write a simple HTTP API command so the ESP will close the relay for 1 second.
Future release : detect physical usage of the buttons to log your coffee usage 
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