first category is for swing traders which you sell-buy, buy-sell and make money with the swings.
second category is for longer term traders / investor. you just buy and hold for some time.
then i must be somewhere in the middle of all this....
i trade "medium term" (if that's a thing). i invest in altcoins when they are at the bottom and stable. you may see this as a nearly horizontal line on the chart. then i sell when that line turned vertical or with a sharp rise (aka coin got pumped). my goal is to minimize the time my bitcoin is invested in these coins so that i can reduce the risks of getting dumped on while earning the most profit possible from the swings.