There was a much bigger benefit. Try writing those words on a whiteboard, repeatedly, and see what that gets you :)
You can argue till you're blue in the face, it's an established shorthand by now. And shorthand has a point - I don't see you writing "random access memory" instead of RAM either.
Once upon a time, RAM was called "core". We should go back to that. I digress...
I'll concede it's easier to write on a whiteboard, but for other situations, it seems rather silly (and very different from the concept of an acronym or initialism).
You can argue till you're blue in the face, it's an established shorthand by now. And shorthand has a point - I don't see you writing "random access memory" instead of RAM either.