$BNB Selling Binance Coin (BNB) on a long position can be beneficial in the long term, as the trader bets on further price increases of the asset. This allows:

To gain profit from the difference between the initial and final price of BNB. For example, if the asset is worth 100% of the initial price, in a long position it can increase by 200%, 500%, or even 1000%.

To limit losses — in a long position the maximum loss is 100% (if the asset depreciates). In a short position, the situation is the opposite: profits are limited, while losses can be huge.