Steam is accepting the bitcoin and that is not really known these days so that is pretty funny, the prices here on the forum are also much better so its logical that it will not really affect the market right now.
What price here on forum are you talking about? People selling games/keys on digital goods?
I think you can save more with steam discounts and promotions.
If your own idea is to save base on discount and promo the i think is not the right idea because not all of the time they give discount or make promo on their srrvices ese you will have to be waiting for long before you get the dicount you want. just use the digita goods section to save your time and money.