I thought steam cracked down on this kind of betting in the last year and banned a bunch of people who were involved? It seems they don't like these gambling sites, they can be easily rigged against you and even if you did win - you might get a steam ban.
Valve wont be going after people who trade skins if thats what you mean, its allowed and encouraged even. Obviously the company Valve benefits greatly, Gabe Newell is a billionaire thanks to such open standards as steam supports. It would be a mistake to go after the ordinary users and I believe thats usually the case for most successful companies.
I know of a few sites that started up and accept skins, its probably still not as widespread as when csgolounge was around and I kinda miss that as I was a big user of that site. I dont mean big amounts, I mean just alot of games with small bets and it was nice they accepted any skin at all. I dont know of any site that is that nice to the little guys now, most sites require just the big items and as said above they then cash you out in tokens or even BTC and let you trade or bet that. I would prefer to stay in skins personally, if anyone knows of such a site I'm interested