You were practically unable to move/rotate/scale control nodes inside of containers, and when you tried the containers would often override it and cause weird behavior. This made animating or moving control nodes in general super finicky and messy.

Transform offsets let you offset the control node and move it around without actually affecting the normal transform, allowing you to do cool effects and animations regardless of whether it's a container or not. It's also something you can easily reset or enable/disable so you can just play the animation and move the offsets back to zero, rather than having to keep track of where the node is actually supposed to be.

If you have a dynamic container, it is sized based on its contents and everything inside of it is positioned based on everything else. If you move something, that impacts everything around it, including the container itself. There are workarounds like having an invisible placeholder and a separate graphical element, but they aren't user-friendly.

Offset transforms allow you to leave the logical version of a thing in place while moving the visual. The demo in the release notes has a grid of icons which get bigger and move when you mouse over them, which would have reflowed the other icons or resized the box before.