It is unusual to play a ukulele with a pick. In my 5+ years of playing, I've never play with pick for more that 2 seconds (it felt so wrong playing with a pick). If you have good strings on your uke, then it should be very easy on your fingers when picking/strumming, therefore a pick won't be necessary. For some instruments, such as a mandolin that has eight metal strings, a pick is recommended, otherwise you'll murder your fingers. A ukulele however, is very easy on your fingers.
Also, when playing with a pick, you risk of scratching the top of your uke. Many uke players, myself included, would never risk scratching the top of our solid wood ukes either. They're not cheap.