Back in the 90s, silver graffiti seemed a bit more common than today. I think a big part of it is, there's not more "dollar silvers" like there used to be. Back then, you could find a lot of random brands of $0.99 silver spray paint that was actually pretty good.
Painting graffiti requires volume, so cheap silver along with a couple cans of Krylon or Rusto and you got a low cost piece. In addition to being cost effective, silvers usually fill in much faster and cover easier than colors.
Silvers were also great for graffiti on bare walls as the silver sits on top really well. With all of the modern paint, this isn't as much of an issue as it used to be since the current graffiti style spray paint covers very well. With that said, the current silvers also perform much better than ever.
To get something filled in very fast, it's hard to beat the modern silver spray paint, but they cost the same as every other color. It's still very worthwhile to rock some silver graffiti. There's a look to it that can't be replicated with any other colors.
