Also impeachment only removes them from office which is far from a complete punishment. They're still completely free people after impeachment, the only right that's taken away is the ability to be President which is a pretty paltry punishment especially for second term Presidents.

There have been impeachment proceedings started against four presidents, all of which would qualify as it being used, even if the presidents weren't successfully impeached. Impeachment proceedings have been completed against 3 presidents and in all cases the senate vote failed to meet the 2/3 supermajority. An impeachment inquiry was also started against Nixon, but he resigned before the house could vote. One could argue that the impeachment inquiry in that case was successful.

The procedure for impeaching federal judges is similar, in that the vote needs first to pass the house, then a supermajority of the senate. In 2009, federal judge Thomas Porteous Jr, was successfully impeached by congress. Congress then also voted to prohibit him from holding future federal office.

https://guides.loc.gov/federal-impeachment/thomas-porteous