That’s not entirely true. While there is indeed a “bounce” interpolation type integrated in blender now, it lacks the flexibility this addon provides. You can only set the amplitude and the easing type.
But sometimes you need to “cheat” in order to get the effect you’re after - and this is what this addon allows you to do. You can offest the phase and amplitude, control the frequency and the frame range over which the effect is active.
And I would like to take this opportunity to thank kgeogeo for this addon!