actually this is what people say when they are too lazy to go into details.
the idea is to buy low when you know price is going high and then sell when you know price won't go any higher.
you can't just put orders and think they MUST be filled.
for instance in Ripple and Ethereum the pumps are over so there is no low anymore. all prices are high and a time for sell. yeah it may bounce back sometimes but the general flow right now is dump-dump-dump.
and for litecoin, nothing is clear at the moment and it is best to stay away.
and remember this is altcoin market we are talking about, it is full of manipulation. the margin trading works in a more logical market not where there is pump and dumps going on.
There's also buying low and selling high when a coin has potential (it's a good idea and could have its price rise a lot from demand, or could just be pumped), but that's unrelated to bot trading because bots are mostly based on buying and selling stable coins based on minor variations during the day.