A big one. No more brittle micro usb, which would eventually become loose and start falling out when charging. Being able to charge my laptop using my phone charger is also good.
That's impressive, how many watts is your phone charger? I would have assumed you could do the opposite but thought the laptop would have laughed when you attached a small stream to it.
I use an old phone charger, when working outside my home. My goal when using it is to keep the charge/uncharge ratio positive. Tho when at home my devices share a 100W charger.