What about snow makes it particularly suited to a poem about the brevity of beauty?

snow is beautiful and cold be like snow ~ Lana Del Rey

Snowflakes could be considered the epitome of brevity: they're transient and can be short lived. The tiniest breath of warm wind or sunlight will melt them and they'll be gone like they never existed. Just like beauty doesn't last forever, snow doesn't either.

Then again, if you live in Canada, where I've been staring at white covered ground for the last six months, snow is not brief at all. It's eternal.