Never sell a bitcoin for USD!! SPEND IT on things or service or commodities.
+1000 I've never understood the logic in selling bitcoins.
The logic resides in the fact that fiat currency is still very stable for the most part. Bitcoin hasn't been over the years. When it comes to finances people want some stability. If they can make some money through a bitcoin investment or they can cashout to prevent losing their entire investment you will have a hard time convincing people not to.