Software has become too bloated, taking too many things into itself.

Someone's system usually has an image viewer, multimedia player, etc. Displaying these things in a browser, messaging program, etc, is pointless. It needlessly multiplies the same functions countless times over.

However, the aesthetic value of in-line images can be argued. This does have its origin in print. Regardless, it isn't essential to have an endless buffer of posted images, videos, audio, etc. We should simply have access to the actual file, and to display according to our own preferences.