I should talk with Valve?
I'm not an expert in video game economics, and I haven't yet seen a strong argument for why a game company would give up control of their own in-game currencies for a currency that they do not (and cannot) control.
If you've got a strong argument for why they should, then YOU should talk with Valve*. They're rational and profit-driven, so if it is in their best interest they should be willing to do it.
*Cue a flood of armchair-game-economists posting their half-baked thoughts here...