This is not a successful leadership trait because harsh leaders will only build resentment in their team, and eventually, the team will resist them. Only arrogent, hard people are harsh. But there are times when this is necessary eg if someone really does something seriously wrong, or commits a crime or they need to show their authority.

It depends on who you're leading, what you're leading, and where you're leading. In MOST cases, I don't think the word harsh describes a good leader, however there is a place for it in desperate situations.

When needed, you must not hesitate to put your foot in someone's ass.