There is more to it than that. It is using optical and digital stabilization, is taking multiple shots at different exposures (likely ISO too), and using computational algorithms to combine all the data into a single image. Quite similar to how the Pixel does this, however the iPhone has far more CPU / GPU horse power behind it and does all of this faster (often better) in my personal tests. I have had decent results doing long exposure in Pro Cam and similar tools with my Xs Max over the last year, however the Pixel's Night Sight typically took a sharper image with less effort overall.
Working on posting some results from the Pixel 3 and Pro Max later today.