..why those side runes matter
Asgard stones are devices which the Asgard use to interact with their technology. Similar to how our own computer mouse is used to interact with selectable "actionable" objects on a computer screen. But with the complexity of Asgard tech, their control stone must likewise allow interactive depth of use. Our computer mouse has normally two buttons on the front, sometimes three. Research is ongoing to allow a deeper level of control through the all-to-familiar computer mouse, which consumer market maintains a large fanbase.
What-if.. the Asgard computer access stone uses those different side runes as we would a computer mouse button? But in a manner that the Asgard stone must be oriented (turned sideways) until that particular rune symbol is facing forward. In episodes where an Asgard control stone was used, did you see that the stone was turned? The most commonly used control subfunctions could be rune symbols already near the front of the stone. Whereas the more specialized the subfunction, the more that particular rune symbol would be located toward the back of the Asgard stone. So this is my hypothesis, that a very complex control interface must likewise require just as complex an interactive device like the Asgard stone.
OR.. through conductance, when two rune glyphs are touched.. a conductive circuit path is formed through the user's skin, which changes the electrical field of the stone slightly, which is detected through the control panel surface, which in turn opens up a new set of subsystem control functions for the user to interact with the Asgard control panel.