actor@work :Why should i make a copy of the animation first?
In some case, you might not get the result you're after, and might not notice it right away.
For example, if you have two rotation keys on the same bone, one at frame 10.52 and another at 10.80, and then use the mentioned method to make them snap, one of the keys will be removed, since they end up overlapping on the same frame.