Design, shape and aspect ratio
Videowalls are designed to be seen up close as they possess resolutions that LED displays do not have. The downside is that you are limited to a rectangular shape in a vertical or horizontal position, with a typical aspect ratio of 16:9 and, in some recent products, 32:9 or similar.
This flexibility of LED panels allows for the creation of large screens both with a standard 16:9 aspect ratio or with any other aspect ratio as well, horizontally or vertically.