yes you need a bot. You decide to short, so you place an order to buy at $58, for this you don't need a bot.

But you know you could mis-identify the trend, so you also want to place an order to buy at $81, if the price ever break through $80 without hitting $58, --- if when you decide to short the price was $81, then double the reason to do so. But you cannot do it before-hand, that would net you a lot of coins immediately. You only want to place that limited order when the price is near $80, and you need a bot to watch that.