Immediate Mode’s kitchen use something like batching to prevent continuous re-rendering. Because if continuous re-rendering is truly happening, it might burn outing our CPU/GPU really badly. Immediate Mode usually used in game development or something alike.
While Immediate Mode is a rendering paradigm where re-rendering (looks like) happened continuously. I use the looks like term because this mode behind the scene is not re-rendeing continuously, but the users who see it thinks it's like re-rendering continuously.
So far, what I understood from those two are: Retained Mode is a rendering paradigm where re-rendering (looks like) only happened when necessary. Things like clicking button in browser triggers some style changes.
I just learned this two cool concepts: Retained Mode and Immediate Mode.