it really depends on what you choose to do.I think they should skip doing a book-style foldable and jump straight to a tri-fold. With book-style, when it's open the screen will have a square aspect ratio, so videos and photos with an aspect ratio of 16:9 or 4:3 are hardly any bigger than when it's closed - you just get bigger black bars. In contrast, with a tri-fold phone the inner screen would have a similar aspect ratio to an iPad, so videos and photos would actually fill the screen, which would be the size of an 10" iPad. Plus you'd get the iPad-style two hand keyboard. See what I mean here:
Finally, with book-style you still need 3 screens but you're always not using at least one, while with tri-fold you can use all 3 screens at the same time.
I don't really watch all that many videos or social media. The front screen is plenty for that since you don't really gain anything except black bars on the inner screen.
I do however read a lot of news sites, forums and reddit, and a bigger screen would work well; even if it is square.