AU allows up to ten images at once, but there is a nice cadence to the Twatter limit of four at a time when telling a story. Also I notice a lot of people on AU only look at the first image and don't realise there are more; the bars overlaid are a bit too subtle.
Also, here on AU it takes forever for photos to actually appear and the same goes for videos to play. I'd love to see more photos/memes and watch more videos but AU makes it very hard to do. I usually just keep scrolling instead of waiting 5 (or way more) minutes to watch a one-minute video to find out wasn't much at all because I've already seen it or it's something I'm not interested in. Since some people post videos with no description, I have to view them before I know.
I don't know if it's any better on a phone, I use my laptop.
I do like AU A LOT more than TS since TS censors posts.