Why is wind directon expressed as "FROM"?

One could easily design a vane that worked the other way.

But they didn't. All weather vanes point into the wind. So those New
Hampshire farmers must have been onto something, since their cast-iron
horses, carriages, sailboats, kiddies etc all point in the direction I
should land the Cub.

Then why don't airports use weathervanes instead of windsocks?