The arch above a bed is one of the oldest gestures in furniture. It comes from architecture, where an arch marks the important place in a wall, and a headboard borrowed it for exactly the same reason: it tells the room where the centre is. Everything else in a bedroom arranges itself around that line.
The fan grain inside the arch is a decision made before any carving happens, at the point where boards are chosen. To get the grain radiating outward from the base, the panel has to be cut from a section of log where the figure runs that way, and the pieces have to be laid in the right order. It is slow, and it is the reason no two of these panels are alike.
Leaving that panel plain, with all the carving pushed out to the frame around it, is a restraint our master Indian artisans practise deliberately. A carver's instinct is to fill the space. Knowing when to stop is the harder skill, and it is what lets the grain do the work here.