[meowtimemania]

If you used curves it'd get complicated deciding where one area starts and the other ends. With hexagons it's easier to divide the world such that (mostly) no hexagon overlaps.

The purpose is to be able to predictably map any coordinate to its associated hexagon.

In database applications this makes it easier to query all data associated with a hexagonal area.

[xhkkffbf]

Why not just squares or rectangles? Is there a simple explanation?

[meowtimemania]

Because it’s hard to cover a sphere in rectangles and have no rectangle overlap.

It’s the same reason soccer balls aren’t covered in squares/rectangles but rather hexagons.

[jt_b]

You want a shape that can represent an approximately equal area, anywhere on a 3 dimensional surface.