When creating animation, it usually depends on small movements. So that usually means that you duplicate a frame and move the object slightly.

It is incredibly impractical to create the duplicated frame at the end of the animation then have to move it next to the frame you just copied.

It would be far better if we had the option to create copied frames right next to the original frame.

In addition, sometimes you need to repeat a sequence. So it would also be useful to be able to select a group of frames to copy them and have them appear right after the original frames.

It is a huge waste of time to move frames individually(as opposed to as a group) from the end of the animation to the middle. This process lends itself to making mistakes. I think there is room for a lot of improvement in this area.