Adjustable bed sides allow you to use mattresses of different thicknesses.
It took a full day of hard work to assemble, and Ikea did not provide even one extra dowel or screw. Since then, this badly designed product has been nothing but trouble. The center piece on top that divides the 2 top drawers is way too heavy, and the holes were not put in correctly. It doesn't hold together in a number of places, and I have had to do major repair work on it, adding braces, nails, and screws, but the chipboard crumbles easily, drawers still don't fit right and connections keep working open. Apparently Ikea has dumped the whole line - a good move, but I'm still stuck with one of these things. If the company wants to offer me a refund, I'm very interested.
IKEA decided to discontinue the medium brown MALM line. So much for IKEA reliability.