Fyi, de_dust is a terrible
map. It's hideously ct-sided, don't even bring it up when you talk about CS:S please
Of course camping is going go nuts on it, because there are only 2 places for the T's to go, and both are easily watched with awps. Makes it very difficult to get by, and it requires a lot of smokes, flashes, and teamwork that won't happen in a pub (generally).
Also, I've never seen a decent player who didn't use flashes. Nades become such an integral part of the game when you start to play on a higher level. In pubs people use them in ridiculous ways just to get easy kills, but those are noobs killing other noobs. You cant play competitively against competent people without using nades. Generally, if you can't afford a full buy in a match, you'll buy nades before you buy armor or a gun - that's how important they are.