What it means
Shorter styles need more screen time and pay more in costs relative to their targets.
In practice
Style should fit your life before it fits your ambitions. Scalping and day trading need hours of full attention at set times; swing trading can be managed around a job with a look at the charts once or twice a day.
It also sets the timeframes to use, the size of stops and targets, and how much costs matter.
What to watch for
Switching style in the middle of a trade is a classic error: a day trade that went wrong becomes a swing trade to avoid taking the loss. Choose one, test it, and judge it over many trades.