[azza2110]

The bracing provided by the backing sheet makes all the difference.

Some of the simple desks the sell are nothing more than a tabletop and four screw in legs. With no bracing the desk is unpleasantly wobbly.

The very popular Ikea cube bookcases (https://www.ikea.com/us/en/cat/kallax-shelving-units-58285/) aren't sold with a backing sheet - thankfully they seem stiff enough without it.