@Rob Had you tested 3.6? There was no need to make a choice, no more than in 3.5 with Twenty Twelve or earlier versions with Twenty Eleven. You could leave things in the default post format and write ordinary posts until the cows came home. Inserting images, galleries, videos, etc. into a default-format post worked normally. Perhaps the row of post format selection buttons across the top of the page would be more distracting than the post format metabox in the right sidebar on account of being larger, but I wouldn't think they'd make a huge difference. (And they go away in the distraction-free editor.)

And your grandmother, frankly, is probably better off installing Jetpack and using the post by email function, because we all know that the WordPress visual editor is an instrument of the devil.