The pavilion features an ingenious architecture, each floor having a different style. The top floor is a Zen meditation hall, built in the Chinese chan style and the middle floor is a hall dedicated to Bodhisattva Kannon, built in the samurai residences Bukke style. The lower, unpainted floor is a secular space, designed for admiring the landscape and it is built in the Shinden style, typically used for the Heian Period mansions.
So the sacred upper floors, housing temple halls, are painted in gold, while the more worldly first floor looks like any other building... But another, simpler explanation is that the first floor is sometimes used for Noh plays and it would be unpractical to play on a slippery surface...
EXIF info:
Nikon D90
Lens: 18-70mm F/3.5-4.5G
Focal Length: 34mm
Aperture: F/5.6
Shutter Speed: 1/100s
ISO Sensitivity: ISO 200