It's different from just stacking exposures, it's a paid app that does progressive animation of exposures for creative effect and says it's "AI-powered" whatever that means.

It's a paid app that I literally have, and all it does is take multiple photos and composite them together. It can either naïvely average them together in-place like a traditional long exposure, or align them using machine learning. I'm actually appalled they use the term "AI" considering who they are but that doesn't matter, it's ML. I don't use any of the animation crap, but the aligned long exposures can be useful for ultrawide takes since that camera is so noisy.

Edit: actually I can't seem to find the setting that aligns them. I seem to remember it being able to do that but maybe it doesn't... which would be disappointing...