you offend my name sir.
krylon is spraypaint. krylon fusion is designed to bond to plastic.
now before everyone poo poos on spraypaint it really does work and does look nice. sure using automotive paint will be cool, until you touch your dried phone and the paint chips off. i know this from experience. i tried to airbrush one of the aforementioned samsung flippers.
if i may offer a few tips BEFORE you paint olly:
masking tape is your friend (obvious)
before you paint, wipe the to-be painted surfaces down with vinegar. this removes all the dirt and oils left on by your fingers and such that will distort and blotchify your paint. obviously after you wipe it down don't touch the part you will paint.
if i think of anything else i'll post. would anyone appreciate it if i wrote a tutorial on doing things like this?